Clastify logo
Clastify logo
Exam prep
Exemplars
Review
HOT

Voronoi Diagrams

Practice exam-style IB Math AI questions for Voronoi Diagrams, aligned with the syllabus and grouped by topic.

Paper
Difficulty
Status
Level
Question 1
SL • Paper 1
Easy
Calculator Permitted

Two emergency call stations are located at A(2,3)A(2,3) and B(8,7)B(8,7) on a coordinate map. A Voronoi edge between their service regions lies on the perpendicular bisector of ABAB.

A

Find the midpoint of ABAB and the gradient of ABAB.

[2]
Write your answer here...
B

Find the equation of the Voronoi edge in the form ax+by+d=0ax+by+d=0, where a,b,dZa,b,d\in\mathbb Z.

[2]
Write your answer here...
C

State the relationship between the distances from a point on this edge to AA and to BB.

[1]
Write your answer here...

0

Question 2
SL • Paper 1
Easy
Calculator Permitted

Two health clinics are located at C(2,6)C(2,6) and D(8,6)D(8,6). Their service regions are separated by a Voronoi edge.

A

Determine the equation of the Voronoi edge.

[2]
Write your answer here...
B

house is located at P(3.5,9)P(3.5,9). State which clinic is nearer to the house and justify your answer.

[2]
Write your answer here...

0

Question 3
SL • Paper 1
Easy
Calculator Permitted

A Voronoi diagram shows three bicycle repair stations AA, BB and CC. Point PP lies inside the cell containing AA, point QQ lies on the edge separating the cells of AA and BB, and point RR is a vertex where the three cells meet. The displayed edges are portions of unbounded rays and continue beyond the boundary of the plotting window.

Voronoi diagram with three stations and query points; each displayed edge extends to the plotting-window boundary.
A

State the repair station nearest to PP.

[1]
Write your answer here...
B

Describe the relationship between the distances QAQA and QBQB.

[1]
Write your answer here...
C

Describe the relationship between RARA, RBRB and RCRC.

[1]
Write your answer here...
D

State what a Voronoi cell represents in this context.

[1]
Write your answer here...

0

Question 4
SL • Paper 1
Medium
Calculator Permitted

Three weather stations have coordinates and recorded rainfall as shown.

StationCoordinatesRainfall (mm)
AA(1,2)(1,2)4242
BB(6,3)(6,3)5555
CC(4,8)(4,8)6161

Nearest-neighbour interpolation is used to estimate rainfall at P(5,5)P(5,5).

A

Calculate the distance from PP to each weather station.

[3]
Write your answer here...
B

Estimate the rainfall at PP.

[1]
Write your answer here...
C

State one limitation of using nearest-neighbour interpolation in this context.

[1]
Write your answer here...

0

Question 5
SL • Paper 1
Medium
Calculator Permitted

A rectangular nature reserve is modelled by 0x80\leq x\leq8 and 0y80\leq y\leq8, where one unit represents 1 km1\ \text{km}. Monitoring sites are located at A(2,3)A(2,3), B(6,3)B(6,3) and C(2,7)C(2,7). Within the reserve, the Voronoi cell of AA is bounded by the reserve boundary and the perpendicular bisectors of ABAB and ACAC.

A

Find the equations of the perpendicular bisectors of ABAB and ACAC.

[2]
Write your answer here...
B

Describe the cell containing AA using inequalities.

[1]
Write your answer here...
C

Calculate the area of the cell containing AA.

[2]
Write your answer here...

0

Question 6
SL • Paper 1
Medium
Calculator Permitted

A regional authority must locate a waste facility as far as possible from its nearest protected habitat. Two candidate Voronoi vertices are V(4,3)V(4,3) and W(7,5)W(7,5). The nearest habitat to VV is at A(1,1)A(1,1), and the nearest habitat to WW is at B(10,2)B(10,2).

A

Calculate the distance from VV to its nearest habitat.

[2]
Write your answer here...
B

Calculate the distance from WW to its nearest habitat.

[2]
Write your answer here...
C

Determine which candidate should be selected.

[1]
Write your answer here...

0

Question 7
SL • Paper 1
Medium
Calculator Permitted

Two delivery depots are located at A(0,0)A(0,0) and B(8,0)B(8,0). A new depot is added at C(4,6)C(4,6). Two sides of the new Voronoi cell lie on the perpendicular bisectors of ACAC and BCBC.

A

Find the equation of the perpendicular bisector of ACAC.

[2]
Write your answer here...
B

Find the equation of the perpendicular bisector of BCBC.

[2]
Write your answer here...
C

Find the point of intersection of these two perpendicular bisectors.

[2]
Write your answer here...

0

Question 8
SL • Paper 1
Medium
Calculator Permitted

A Voronoi edge separating two sites AA and BB has equation y=x+6y=-x+6. Site BB has coordinates (5,4)(5,4).

A

Find the equation of the line through AA and BB.

[2]
Write your answer here...
B

Find the midpoint of ABAB.

[2]
Write your answer here...
C

Find the coordinates of site AA.

[2]
Write your answer here...

0

Question 9
HL • Paper 1
Medium
Calculator Permitted

A bounded Voronoi cell for a wildlife monitoring station has vertices (1,1)(1,1), (6,1)(6,1), (7,4)(7,4), (4,7)(4,7) and (1,5)(1,5), listed in order around the cell. One coordinate unit represents 1 km1\ \text{km}. The estimated animal density throughout the cell is 1818 animals per square kilometre.

Bounded Voronoi cell with five vertices in cyclic order.
A

Calculate the area of the Voronoi cell.

[4]
Write your answer here...
B

Estimate the number of animals in this cell.

[2]
Write your answer here...

0

Question 10
HL • Paper 1
Medium
Calculator Permitted

Existing service centres are located at A(0,0)A(0,0) and B(10,0)B(10,0). A new centre is added at N(5,4)N(5,4). Its new Voronoi cell is determined in part by the perpendicular bisectors of ANAN and BNBN.

A

Find the equation of the perpendicular bisector of ANAN.

[2]
Write your answer here...
B

Find the equation of the perpendicular bisector of BNBN.

[2]
Write your answer here...
C

Determine whether P(3,2)P(3,2) belongs to the new centre's Voronoi cell. Justify your answer.

[2]
Write your answer here...

0

Question 11
HL • Paper 1
Medium
Calculator Permitted

A proposed facility must maximize its distance from the nearest settlement. The only candidate locations are Voronoi vertices V1(4,3)V_1(4,3), V2(8,6)V_2(8,6) and V3(5,9)V_3(5,9). A nearest settlement to each vertex is respectively A(1,1)A(1,1), B(11,2)B(11,2) and C(2,11)C(2,11).

A

Calculate the nearest-settlement distance for each candidate.

[3]
Write your answer here...
B

Determine where the facility should be located.

[2]
Write your answer here...
C

Explain why the distance to the nearest settlement, rather than the distance to every settlement, is used for this decision.

[1]
Write your answer here...

0

Question 12
HL • Paper 1
Medium
Calculator Permitted

Air-quality sensors A(2,2)A(2,2), B(6,2)B(6,2) and C(10,2)C(10,2) record pollution indices 1414, 2020 and 1717, respectively. Nearest-neighbour interpolation is used along the horizontal route y=2y=2, for 0x120\leq x\leq12.

A

Find the two points on the route where the nearest-neighbour estimate changes.

[2]
Write your answer here...
B

Write down the nearest-neighbour estimate I(x)I(x) along the route, excluding the two boundary points.

[2]
Write your answer here...
C

Calculate the mean estimated pollution index over the whole route.

[2]
Write your answer here...

0

Question 13
HL • Paper 1
Medium
Calculator Permitted

Three communication towers are located at A(0,0)A(0,0), B(6,2)B(6,2) and C(2,8)C(2,8). A Voronoi vertex VV is equidistant from all three towers.

A

Find the equation of the perpendicular bisector of ABAB.

[2]
Write your answer here...
B

Find the equation of the perpendicular bisector of ACAC.

[2]
Write your answer here...
C

Determine the coordinates of VV.

[2]
Write your answer here...
D

Calculate the common distance from VV to the three towers.

[1]
Write your answer here...

0

Question 14
HL • Paper 1
Medium
Calculator Permitted

The Voronoi edge separating sites AA and BB has equation 2xy3=02x-y-3=0. Site BB is located at (8,2)(8,2).

A

Find the equation of the line containing AA and BB.

[2]
Write your answer here...
B

Find the midpoint of ABAB.

[2]
Write your answer here...
C

Find the coordinates of AA.

[2]
Write your answer here...

0

Question 15
HL • Paper 1
Medium
Calculator Permitted

Four sites are located at A(3,0)A(-3,0), B(3,0)B(3,0), C(0,4)C(0,4) and D(0,6)D(0,-6). The perpendicular bisector of ABAB is the line x=0x=0. Only part of this line is a Voronoi edge because sites CC and DD cut it off.

A

For a point P(0,y)P(0,y), write expressions for PA2PA^2, PC2PC^2 and PD2PD^2.

[3]
Write your answer here...
B

Find the values of yy for which PP is no farther from AA and BB than it is from either CC or DD.

[3]
Write your answer here...
C

State the Voronoi edge shared by the cells of AA and BB.

[1]
Write your answer here...

0

Question 16
HL • Paper 1
Medium
Calculator Permitted

An existing Voronoi diagram has sites A(0,0)A(0,0), B(8,0)B(8,0) and C(4,8)C(4,8). Its three cells meet at N(4,3)N(4,3). A new site is added at the point NN.

A

Verify that NN is equidistant from AA, BB and CC.

[2]
Write your answer here...
B

Find the equation of the perpendicular bisector of the segment joining the new site NN to AA.

[2]
Write your answer here...
C

Explain which of the three existing Voronoi cells are affected by adding the new site.

[2]
Write your answer here...

0

Question 17
SL • Paper 2
Medium
Calculator Permitted

Two mobile libraries are located at A(1,2)A(1,2) and B(7,6)B(7,6). The boundary between their service regions is the perpendicular bisector of ABAB. A second straight line has equation y=x1y=x-1.

Coordinate-plane map of the two library sites, the perpendicular-bisector line, the second straight line, and their intersection point.
A
I.

Find the midpoint of ABAB and the gradient of ABAB.

[2]
Write your answer here...
II.

Hence find the equation of the perpendicular bisector of ABAB, giving your answer in the form ax+by=cax+by=c, where aa, bb and cc are integers.

[3]
Write your answer here...
B
I.

Find the coordinates of the intersection point of the two lines.

[2]
Write your answer here...
II.

resident lives at P(5,3)P(5,3). Determine which of AA or BB is closer to PP. Justify your answer using distances.

[2]
Write your answer here...

0

Question 18
SL • Paper 2
Medium
Calculator Permitted

Three soil-moisture stations have the following coordinates and readings. Nearest-neighbour interpolation is used along the path y=5y=5, for 0x80\leq x\leq8.

StationCoordinatesMoisture index
AA(0,1)(0,1)2828
BB(6,1)(6,1)4444
CC(3,7)(3,7)6565
Stations, path y=5, and Voronoi boundaries.
A
AI.

Find the value of xx at which the line y=5y=5 meets the perpendicular bisector of ACAC, and state whether this point lies on the specified path.

[2]
Write your answer here...
AII.

Find the value of xx where the path crosses the perpendicular bisector of BCBC.

[3]
Write your answer here...
B
BI.

Write down the nearest-neighbour moisture estimate along each section of the path, excluding boundary points.

[2]
Write your answer here...
BII.

Calculate the mean estimated moisture index along the path.

[2]
Write your answer here...

0

Question 19
SL • Paper 2
Medium
Calculator Permitted

A square wildlife reserve is modelled by 0x100\leq x\leq10 and 0y100\leq y\leq10, where one unit represents 1 km1\ \text{km}. A ranger station is at R(3,3)R(3,3). Its neighbouring stations are at E(7,3)E(7,3), N(3,7)N(3,7) and S(0,0)S(0,0).

Square reserve with stations and Voronoi cell of R.
A
I.

Find the perpendicular bisectors of RERE, RNRN and RSRS.

[3]
Write your answer here...
II.

Write inequalities describing the Voronoi cell containing RR.

[2]
Write your answer here...
B
I.

Calculate the area of the cell containing RR.

[3]
Write your answer here...
II.

The estimated animal density throughout this cell is 1212 animals per square kilometre. Estimate the number of animals in the cell.

[2]
Write your answer here...

0

Question 20
SL • Paper 2
Medium
Calculator Permitted

A regional authority must locate a hazardous-material store as far as possible from its nearest conservation site. Three candidate locations are V1(3,4)V_1(3,4), V2(8,3)V_2(8,3) and V3(6,8)V_3(6,8). The nearest conservation sites to these locations are C(2,5)C(2,5), B(10,7)B(10,7) and B(10,7)B(10,7), respectively.

Coordinate map of the three candidate locations, the conservation sites, and the river $y=0$.
A
I.

Calculate the distance from each candidate vertex to its nearest conservation site.

[3]
Write your answer here...
II.

Identify all candidates that maximize the distance to the nearest conservation site.

[2]
Write your answer here...
B
I.

The river is represented by y=0y=0. Of the optimal candidates, determine which is farther from the river.

[2]
Write your answer here...
II.

Explain why candidate locations, rather than the conservation sites, are considered as possible locations.

[1]
Write your answer here...

0

Question 21
SL • Paper 2
Medium
Calculator Permitted

A bounded Voronoi cell for a rainfall gauge has vertices (1,2)(1,2), (5,1)(5,1), (8,4)(8,4), (6,8)(6,8) and (2,7)(2,7), listed in order. One coordinate unit represents 1 km1\ \text{km}. The gauge records rainfall of 72 mm72\ \text{mm}.

Voronoi cell for rainfall gauge.
A
I.

Use the shoelace formula to calculate the area of the cell.

[3]
Write your answer here...
II.

State the rainfall estimate at every point strictly inside this cell when nearest-neighbour interpolation is used.

[2]
Write your answer here...
B
I.

Estimate the total volume of rainfall falling on the cell, in cubic metres.

[3]
Write your answer here...
II.

State one limitation of this estimate.

[1]
Write your answer here...

0

Question 22
HL • Paper 3
Medium
Calculator Permitted

Four marine monitoring stations have Voronoi-cell areas and recorded water temperatures as shown. Nearest-neighbour interpolation assigns each point in a cell the temperature at its station.

Station

Voronoi-cell area / km2\mathrm{km^2}

Recorded temperature / C^\circ\text{C}

A

18

14

B

25

17

C

31

20

D

26

16

A
I.

Verify that the total surveyed area is 100 km2100\ \text{km}^2.

[2]
Write your answer here...
II.

Calculate the area-weighted mean estimated temperature.

[2]
Write your answer here...
B

station with temperature 20C20^\circ\text{C} has its cell reduced from 3131 to 24 km224\ \text{km}^2 when a new station is added. State the area transferred from the old cell.

[2]
Write your answer here...
C

Discuss one limitation of nearest-neighbour interpolation for estimating sea temperature.

[2]
Write your answer here...

0

Question 23
SL • Paper 2
Hard
Calculator Permitted

Four charging stations are located at (2,2)(2,2), (8,2)(8,2), (8,8)(8,8) and (2,8)(2,8). A fifth station NN is added at (5,5)(5,5).

Four stations at the corners of a square and station N at the centre, with the Voronoi cell outline shown.
A
I.

Find the equations of the perpendicular bisectors between NN and each of the four existing stations.

[4]
Write your answer here...
II.

Read the four vertices of the Voronoi cell containing NN from the diagram.

[2]
Write your answer here...
B
I.

Calculate the area of the new station's Voronoi cell.

[2]
Write your answer here...
II.

Explain why all four original cells lose the same area when NN is added.

[2]
Write your answer here...

0

Question 24
SL • Paper 2
Hard
Calculator Permitted

A Voronoi edge between two archaeological survey sites has equation y=2x+1y=2x+1. One of the sites is A(2,7)A(2,7), and the other site is BB.

Coordinate plane showing the Voronoi edge with sites A and P.
A
I.

Find the equation of the line containing AA and BB.

[2]
Write your answer here...
II.

Find the midpoint of ABAB.

[3]
Write your answer here...
B
I.

Hence find the coordinates of BB.

[2]
Write your answer here...
II.

Determine whether P(4,9)P(4,9) is closer to AA than to BB.

[2]
Write your answer here...

0

Question 25
SL • Paper 2
Hard
Calculator Permitted

Three flood-response hubs are located at A(2,1)A(-2,1), B(4,3)B(4,3) and C(1,7)C(1,7). Their Voronoi cells meet at a vertex VV.

Coordinate map of hubs A, B, C, incident Q, and the perpendicular bisectors.
A
I.

Find the equations of the perpendicular bisectors of ABAB and ACAC.

[4]
Write your answer here...
II.

Hence find the coordinates of VV.

[2]
Write your answer here...
B
I.

Calculate the common distance from VV to the three hubs.

[2]
Write your answer here...
II.

An incident occurs at Q(0,5)Q(0,5). Determine the nearest response hub.

[2]
Write your answer here...

0

Question 26
HL • Paper 2
Hard
Calculator Permitted

Three protected nesting sites are located at A(1,1)A(1,1), B(9,1)B(9,1) and C(4,8)C(4,8). A candidate wind turbine location VV is the Voronoi vertex equidistant from these sites. A second candidate WW has nearest-site distance 5.105.10 units.

Map of sites A, B, C and candidate points V and W.
A
I.

Find the equations of the perpendicular bisectors of ABAB and ACAC.

[3]
Write your answer here...
II.

Hence find the coordinates of VV.

[3]
Write your answer here...
B
I.

Calculate the nearest-site distance at VV.

[2]
Write your answer here...
II.

Determine which candidate should be chosen to maximize the distance from the nearest nesting site. Justify your answer.

[2]
Write your answer here...

0

Question 27
HL • Paper 2
Hard
Calculator Permitted

A rectangular agricultural district has area 120 km2120\ \text{km}^2 and is divided into three regions, one associated with each sensor. The region associated with sensor AA has vertices (0,0)(0,0), (5,0)(5,0), (6,4)(6,4), (3,7)(3,7) and (0,6)(0,6), listed in order. The region associated with sensor BB has area 41 km241\ \text{km}^2. Sensors AA, BB and CC record crop indices 1212, 2020 and 3232, respectively. For this question, each region is assigned the crop index recorded by its associated sensor.

Given rectangular district, region A boundary, and sensor sites; no nearest-sensor partition is implied.
A
I.

Calculate the area of the region associated with AA.

[3]
Write your answer here...
II.

Hence find the area of the region associated with CC.

[2]
Write your answer here...
B
I.

Using this constant-per-region interpolation, calculate the mean estimated crop index over the district.

[3]
Write your answer here...
II.

Explain why this model produces sudden changes in the estimated crop index at boundaries between regions.

[2]
Write your answer here...

0

Question 28
HL • Paper 2
Hard
Calculator Permitted

A chemical-storage facility must be placed as far as possible from its nearest residential area. Candidate VV is the intersection of the lines 2x+y=112x+y=11 and x2y=1x-2y=-1. Two other candidates are W(8,5)W(8,5) and U(5,9)U(5,9). Nearest residential sites to VV, WW and UU are A(1,0)A(1,0), B(11,2)B(11,2) and C(2,7)C(2,7), respectively.

Planning map of the known candidate points and residential sites.
A
I.

Find the coordinates of VV.

[2]
Write your answer here...
II.

Calculate the nearest-residential-site distance for each candidate.

[3]
Write your answer here...
B
I.

Determine the preferred candidate using the maximin criterion.

[2]
Write your answer here...
II.

Candidate WW is later excluded because it lies in a flood zone. Determine the next preferred candidate and explain why.

[2]
Write your answer here...

0

Question 29
HL • Paper 3
Hard
Calculator Permitted

A rectangular forest is modelled by 0x120\leq x\leq12 and 0y120\leq y\leq12, where one coordinate unit represents 1 km1\ \text{km}. Ranger stations are located at A(2,2)A(2,2), B(10,2)B(10,2) and C(6,10)C(6,10). Nearest-station regions are modelled using a Voronoi diagram.

Forest boundary with ranger stations and hiker point.
A
I.

Find the equations of the perpendicular bisectors of ABAB and ACAC.

[2]
Write your answer here...
II.

Hence find the Voronoi vertex and its distance from each station.

[2]
Write your answer here...
B

The cell containing AA is bounded by x=0x=0, y=0y=0, x=6x=6 and y=12x+8y=-\frac12x+8. Calculate its area.

[2]
Write your answer here...
C

hiker is at P(7,6)P(7,6). Determine the station assigned to the hiker and justify your answer.

[2]
Write your answer here...

0

Question 30
HL • Paper 3
Hard
Calculator Permitted

Initially, sensors AA, BB and CC are at positions x=0x=0, x=7x=7 and x=13x=13 and record moisture indices 1212, 2020 and 88, respectively. Nearest-neighbour interpolation is used along the channel. The data for sensor NN, to be installed in part b, are shown in the table but are not used initially.

Sensor or boundary

Position x [km]

Moisture index

A

0

12

B

7

20

N (part b)

9

16

C

13

8

Channel end

16

Not applicable

A
I.

Find the positions where the nearest-neighbour estimate changes.

[2]
Write your answer here...
II.

Calculate the mean estimated moisture index over the whole channel.

[2]
Write your answer here...
B

new sensor NN is installed at x=9x=9 and records an index of 1616. Find the interval assigned to NN.

[2]
Write your answer here...
C

Show that adding NN does not change the mean estimated index over the channel.

[2]
Write your answer here...

0

Question 31
HL • Paper 3
Hard
Calculator Permitted

Four emergency beacons are located at the corners A(1,1)A(1,1), B(9,1)B(9,1), C(9,9)C(9,9) and D(1,9)D(1,9) of a square region. A fifth beacon is added at N(5,5)N(5,5).

Square region with four corner beacons and a central beacon.
A
I.

Find the perpendicular bisectors of NANA and NBNB.

[2]
Write your answer here...
II.

Using symmetry, write down the other two boundaries of the cell containing NN.

[2]
Write your answer here...
B

Find the vertices and area of the cell containing NN.

[2]
Write your answer here...
C

State which original cells are changed when NN is added, and explain why.

[2]
Write your answer here...

0

Question 32
HL • Paper 3
Hard
Calculator Permitted

A conservation authority must locate a chemical-storage site as far as possible from the nearest protected habitat. Three internal Voronoi vertices are V(4,5)V(4,5), W(9,4)W(9,4) and U(7,9)U(7,9). The protected habitat points considered are A(1,1)A(1,1), B(12,0)B(12,0) and C(7,3)C(7,3). For each candidate, the nearest-habitat distance is the distance to the closest of these three points.

Candidate locations, protected habitat points, entrance, and restricted zone.
A
I.

Calculate the nearest-habitat distance for each candidate.

[2]
Write your answer here...
II.

Determine the preferred location under the authority's criterion.

[2]
Write your answer here...
B

restricted zone is the circle with centre (8,8)(8,8) and radius 22. Determine whether the preferred location is permitted.

[2]
Write your answer here...
C

The remaining candidates are VV and WW. The authority chooses the candidate with the greater nearest-habitat distance; if tied, it chooses the tied candidate nearer the entrance at (0,0)(0,0). Determine the final location.

[2]
Write your answer here...

0

Question 33
HL • Paper 3
Hard
Calculator Permitted

The bounded Voronoi cell of an ecological sampling site has vertices (1,1)(1,1), (7,1)(7,1), (8,4)(8,4), (5,8)(5,8) and (1,6)(1,6), listed in order. One coordinate unit represents 1 km1\ \text{km}. Nearest-neighbour interpolation assigns a density of 2424 nesting pairs per square kilometre throughout the cell.

Pentagonal Voronoi cell with labelled vertices and an interior sampling site.
A
I.

Calculate the area of the cell.

[2]
Write your answer here...
II.

Estimate the number of nesting pairs in the cell.

[2]
Write your answer here...
B

new site removes 6.5 km26.5\ \text{km}^2 from this cell. Calculate the revised estimate, assuming the density assigned to the remaining cell is unchanged.

[2]
Write your answer here...
C

Explain why the estimate of 900900 should not be interpreted as an exact count.

[2]
Write your answer here...

0

Question 34
HL • Paper 3
Hard
Calculator Permitted

Disease-monitoring sites are at A(0,0)A(0,0), B(8,0)B(8,0) and C(0,6)C(0,6) and record infection indices 66, 1414 and 1010, respectively. Their Voronoi cells meet at VV.

Coordinate map showing the three disease-monitoring sites and their recorded infection indices.
A
I.

Find the coordinates of VV.

[2]
Write your answer here...
II.

Verify that VV is equidistant from the three sites.

[2]
Write your answer here...
B

Explain why nearest-neighbour interpolation does not give a unique infection index at VV.

[2]
Write your answer here...
C

researcher assigns the arithmetic mean of tied readings at a Voronoi vertex. Find the assigned index and discuss whether this remains nearest-neighbour interpolation.

[2]
Write your answer here...

0

Question 35
HL • Paper 3
Hard
Calculator Permitted

A noise-generating facility must be positioned as far as possible from the nearest residential site. Three admissible internal Voronoi vertices and their distances to the nearest residence are shown in the table.

Vertex

Coordinates

Nearest-residence distance [km]

P

(3, 8)

5.40

Q

(9, 7)

6.10

R

(6, 12)

6.10

A
I.

Identify all candidates that maximize the distance to the nearest residence.

[2]
Write your answer here...
II.

power connection is at (12,12)(12,12). Determine which maximizing candidate is nearer the connection.

[2]
Write your answer here...
B

State the final choice if distance from residences is the primary criterion and connection distance is used only to break a tie.

[2]
Write your answer here...
C

Explain why choosing the point with the greatest average distance from all residences could give a different result.

[2]
Write your answer here...

0

Question 36
HL • Paper 3
Hard
Calculator Permitted

A missing rescue post SS has a Voronoi edge with post A(0,2)A(0,2) on the line x=3x=3. It also has a Voronoi edge with post B(6,10)B(6,10) on the line y=6y=6.

Coordinate diagram with posts A, B, and P, plus the candidate perpendicular bisectors $x=3$ and $y=6$. The displayed full lines are supporting lines and are not necessarily complete Voronoi edges.
A
I.

Use the edge x=3x=3 to determine SS.

[2]
Write your answer here...
II.

Verify that y=6y=6 is the perpendicular bisector of SBSB.

[2]
Write your answer here...
B

Point P(5,4)P(5,4) lies between the two given edges. Determine whether PP is nearer to SS than to both AA and BB.

[2]
Write your answer here...
C

Explain why the full lines x=3x=3 and y=6y=6 need not both appear as complete edges in the final Voronoi diagram.

[2]
Write your answer here...

0

Question 37
HL • Paper 2
Hard
Calculator Permitted

A research station S(4,4)S(4,4) has neighbouring stations A(0,2)A(0,2), B(8,2)B(8,2), C(7,8)C(7,8) and D(1,8)D(1,8). Its Voronoi cell is bounded by the perpendicular bisectors between SS and these four sites.

Voronoi cell for S, neighbouring stations, and the sample rectangle.
A
I.

Show that the cell containing SS is described by the inequalities
2x+y7,2xy9,6x+8y81,6x+8y332x+y\geq7,\quad 2x-y\leq9,\quad 6x+8y\leq81,\quad -6x+8y\leq33

[4]
Write your answer here...
II.

Find the coordinates of the four vertices of the cell.

[2]
Write your answer here...
B
I.

Calculate the area of the Voronoi cell.

[3]
Write your answer here...
II.

sample point is chosen uniformly from the rectangle 0x80\leq x\leq8, 1y8-1\leq y\leq8. Find the probability that it lies in the cell containing SS.

[3]
Write your answer here...

0

Question 38
HL • Paper 2
Hard
Calculator Permitted

Two existing data centres are at A(0,0)A(0,0) and B(10,0)B(10,0). A third centre is placed at N(t,6)N(t,6), where 0<t<100<t<10. The perpendicular bisectors of ABAB and ANAN meet at VV.

Fixed centres A and B, with N moving along y=6.
A
I.

Show that the coordinates of VV are
V(5,t210t+3612)V\left(5,\frac{t^2-10t+36}{12}\right)

[3]
Write your answer here...
II.

Find the values of tt for which VV lies on the line y=2y=2.

[2]
Write your answer here...
B
I.

Find the value of tt for which the distance from VV to AA is minimized.

[3]
Write your answer here...
II.

Calculate this minimum distance.

[2]
Write your answer here...

0

Question 39
HL • Paper 2
Hard
Calculator Permitted

A rectangular delivery region is modelled by 0x100\leq x\leq10 and 0y80\leq y\leq8. Existing depots are at A(0,0)A(0,0), B(10,0)B(10,0) and C(4,9)C(4,9). A new depot is added at N(4,3)N(4,3).

Coordinate diagram of the delivery region, depots A, B, C and N, and the boundary of N's Voronoi cell. Render with a true equal data-unit aspect ratio, so one x-unit equals one y-unit, while keeping labels readable and showing C(4,9).
A
I.

Find inequalities representing points that are at least as close to NN as to each of AA, BB and CC.

[3]
Write your answer here...
II.

Find the vertices of the new Voronoi cell after it is clipped by the rectangular boundary.

[3]
Write your answer here...
B
I.

Calculate the area of the new Voronoi cell.

[3]
Write your answer here...
II.

customer is chosen uniformly at random from the delivery region. Find the probability that the new depot is the customer's nearest depot.

[3]
Write your answer here...

0

Question 40
HL • Paper 2
Hard
Calculator Permitted

The Voronoi edge between an unknown monitoring site SS and site A(0,0)A(0,0) has equation x+2y=5x+2y=5. The edge between SS and site B(8,2)B(8,2) is claimed to have equation y=3x12y=3x-12.

Sites A and B with the two Voronoi edge lines.
A
I.

Find the equation of the line containing AA and SS.

[2]
Write your answer here...
II.

Hence find the coordinates of SS.

[4]
Write your answer here...
B
I.

Verify that y=3x12y=3x-12 is the perpendicular bisector of SBSB.

[3]
Write your answer here...
II.

Find the vertex where the two stated Voronoi edges intersect.

[1]
Write your answer here...

0

Question 41
HL • Paper 2
Hard
Calculator Permitted

Two ferry terminals are at A(2,2)A(2,2) and B(10,6)B(10,6). Their ordinary Euclidean Voronoi edge crosses a straight coastal road with equation y=1y=1. A passenger terminal is proposed at P(7,1)P(7,1).

Two ferry terminals, their Voronoi edge, coastal road y=1, and proposed terminal P.
A
I.

Find the equation of the perpendicular bisector of ABAB.

[4]
Write your answer here...
II.

Find the point where this edge crosses the coastal road.

[2]
Write your answer here...
B
I.

Using Euclidean distance, determine which ferry terminal is nearer to PP.

[2]
Write your answer here...
II.

The road network requires passengers to travel only horizontally or vertically. Under this rule, the travel distances from PP to AA and BB are 72+12|7-2|+|1-2| and 710+16|7-10|+|1-6|, respectively. Determine the nearer terminal and evaluate the suitability of the Euclidean Voronoi model.

[2]
Write your answer here...

0

Question 42
HL • Paper 3
Hard
Calculator Permitted

A Voronoi edge separating archaeological survey sites AA and BB lies on 3x+4y25=03x+4y-25=0. Site BB is located at (9,7)(9,7).

Voronoi edge 3x+4y-25=0 with site B at (9,7).
A
I.

Find the coordinates of the midpoint MM of ABAB.

[2]
Write your answer here...
II.

Hence determine the coordinates of AA.

[2]
Write your answer here...
B

Determine which of AA and BB is closer to P(4,4)P(4,4).

[2]
Write your answer here...
C

Explain why reflecting BB in the line containing the Voronoi edge produces AA.

[2]
Write your answer here...

0

Question 43
HL • Paper 3
Hard
Calculator Permitted

A city compares ordinary Euclidean distance with Manhattan distance, defined by d=x2x1+y2y1d=|x_2-x_1|+|y_2-y_1|. Two depots are at A(2,2)A(2,2) and B(8,6)B(8,6).

Coordinate map showing depots A, B and comparison point P.
A
I.

On the line y=4y=4, find the point equidistant from AA and BB using Manhattan distance.

[2]
Write your answer here...
II.

On the line x=5x=5, find the point equidistant from AA and BB using Manhattan distance.

[2]
Write your answer here...
B

For P(4,5)P(4,5), compare its assignments under Manhattan and Euclidean distance.

[2]
Write your answer here...
C

Explain why the two metrics can produce different Voronoi cells in this context.

[2]
Write your answer here...

0

Question 44
HL • Paper 3
Hard
Calculator Permitted

Two coastal transmitters are located at A(0,0)A(0,0) and B(12,0)B(12,0). A third transmitter is located at N(6,t)N(6,t), where t>0t>0. The three Voronoi cells meet at VV.

Feature

Data

Note

A

(0,0)

fixed transmitter

B

(12,0)

fixed transmitter

Midpoint of AB

(6,0)

halfway between A and B

N

(6,t), t > 0

third transmitter

V

equidistant from A, B and N

Voronoi vertex

Coastal region condition

6 ≤ t ≤ 12

used in part (c)

A
I.

Explain why VV has xx-coordinate 66.

[2]
Write your answer here...
II.

Show that V=(6,t2362t)V=\left(6,\frac{t^2-36}{2t}\right).

[2]
Write your answer here...
B

Determine the values of tt for which VV lies on or above the xx-axis.

[2]
Write your answer here...
C

The coastal region requires 6t126\leq t\leq12. Determine the greatest possible common distance from VV to the three transmitters.

[2]
Write your answer here...

0

Question 45
HL • Paper 3
Hard
Calculator Permitted

Delivery hubs are located at L(0,0)L(0,0), R(14,0)R(14,0) and N(7,6)N(7,6). A vehicle travels east along the horizontal road y=hy=h from x=0x=0 to x=14x=14 at constant speed.

Voronoi hubs L, R, N with bisectors.
A
I.

Find the perpendicular bisectors of LNLN and RNRN.

[2]
Write your answer here...
II.

Show that the length of road inside the cell of NN is 12h+137\frac{12h+13}{7}, assuming the road intersects both boundaries of the cell of NN within 0x140\le x\le14; equivalently, 1312h8512-\frac{13}{12}\le h\le\frac{85}{12}.

[2]
Write your answer here...
B

The vehicle spends 25%25\% of its journey in the cell of NN. Determine hh.

[2]
Write your answer here...
C

Explain why the percentage of travel time equals the percentage of route length in this model.

[2]
Write your answer here...

0

Question 46
HL • Paper 3
Hard
Calculator Permitted

Warehouses are located at the corners A(0,0)A(0,0), B(16,0)B(16,0), C(16,12)C(16,12) and D(0,12)D(0,12) of a rectangular industrial zone. A new warehouse is added at N(8,6)N(8,6).

Coordinate diagram of the rectangular industrial zone with the four corner warehouses and the new warehouse.
A
I.

Find the perpendicular bisectors of NANA and NBNB.

[2]
Write your answer here...
II.

Write inequalities describing the side of each boundary containing NN.

[2]
Write your answer here...
B

Determine whether P(7,2)P(7,2) can belong to the new cell by testing these two inequalities.

[2]
Write your answer here...
C

Explain why satisfying only these two inequalities is insufficient to prove that PP is in the cell of NN.

[2]
Write your answer here...

0

Question 47
HL • Paper 3
Hard
Calculator Permitted

At an unsampled location PP, the nearest environmental station is AA, with reading 1818. If PP is inserted as a temporary site, it takes fractions 0.200.20, 0.500.50 and 0.300.30 of its new cell from stations AA, BB and CC, whose readings are 1818, 2424 and 1515. A natural-neighbour estimate uses these fractions as weights.

A schematic Voronoi diagram showing a newly inserted point P and the portions of its new cell taken from three neighbouring station cells.
A
I.

Verify that the three fractions form valid interpolation weights.

[2]
Write your answer here...
II.

Calculate the natural-neighbour estimate at PP.

[2]
Write your answer here...
B

State the nearest-neighbour estimate at PP and compare it with the natural-neighbour estimate.

[2]
Write your answer here...
C

Explain why natural-neighbour interpolation can produce a smoother model than nearest-neighbour interpolation.

[2]
Write your answer here...

0

Question 48
HL • Paper 3
Hard
Calculator Permitted

A fixed communications site is at A(0,0)A(0,0). A second site moves along the line y=4y=4 and has coordinates B(t,4)B(t,4), where t>0t>0. The perpendicular bisector of ABAB meets the positive xx-axis at XX.

Coordinate diagram showing fixed site A, moving site B on y = 4, and the perpendicular bisector meeting the positive x-axis at X for t = 6.
A
I.

Show that the perpendicular bisector has equation 2tx+8y=t2+162tx+8y=t^2+16.

[2]
Write your answer here...
II.

Hence show that the xx-coordinate of XX is t2+8t\frac{t}{2}+\frac{8}{t}.

[2]
Write your answer here...
B

Determine the value of tt for which XX is closest to the origin.

[2]
Write your answer here...
C

Find the minimum possible distance OXOX and interpret this result in terms of the moving site.

[2]
Write your answer here...

0


Vectors