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Ans Coursebook U18

The document provides answers to various exercises related to area, perimeter, and volume from a mathematics coursebook. It includes calculations and results for different shapes and dimensions, as well as unit conversions. The exercises cover both theoretical and practical applications of geometric concepts.

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5 views2 pages

Ans Coursebook U18

The document provides answers to various exercises related to area, perimeter, and volume from a mathematics coursebook. It includes calculations and results for different shapes and dimensions, as well as unit conversions. The exercises cover both theoretical and practical applications of geometric concepts.

Uploaded by

김미란
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Answers to Coursebook exercises

18 Area, perimeter and volume

F Exercise 18.1
1 a mm2 b cm2 c m2 d m2
2 a 600 b 720 c 30 000 d 54 000 e 9 f 8.65
g 2 h 4.8 i 12.5
3 No. 0.25 × 1000 × 1000 = 250 000

F Exercise 18.2
1 a 8 cm2, 12 cm b 20 m2, 18 m c 40 mm2, 26 mm d 25 cm2, 20 cm
e 56 m2, 30 m f 36 mm2, 30 mm
2 31 080 mm2
3 a 10 m2 b 13 m
4 a 3m b 14 m
5 0.6 cm , 60 mm
2 2

6 Rectangle Length Width Area Perimeter


A 8 mm 6 mm 48 mm 2
28 mm
B 7 cm 4 cm 28 cm 2
22 mm
C 12 m 5m 60 m2 34 m
D 8 cm 3m 24 cm2 22 cm
E 8.5 mm 1.5 mm 12.75 mm 2
20 mm

7 3.6 m2
8 Tanisha. 1 cm by 24 cm, 2 cm by 12 cm, 3 cm by 8 cm, 4 cm by 6 cm

F Exercise 18.3
1 a Method 1 Method 2
Area A = 6 × 2 = 12 cm2 Area A = 2 × 2 = 4 cm2
Area B = 4 × 4 = 16 cm2 Area B = 6 × 4 = 24 cm2
Total area = 12 + 16 = 28 cm2
Total area = 4 + 24 = 28 cm2
b Both methods give the same answer, 28 cm2.
2 a area: 75 cm2, perimeter: 38 cm b area: 86 cm2, perimeter: 44 cm
c area: 19 m2, perimeter: 18 m d area: 510 mm2, perimeter: 114 mm
3 268 cm2
4 a 60 cm2 b 742 cm2
5 Area B = 6 × 2 = 12 cm2, area C = 20 × 2 = 40 cm2, total area = 92 cm2. Perimeter = 64 cm

Copyright Cambridge University Press 2012 Cambridge Checkpoint Mathematics 7 1


Unit 18 Answers to Coursebook exercises

F Exercise 18.4
1 a 56 cm3 b 90 cm3 c 54 cm3
2 a 12 m3 b 360 mm3
3 She didn’t change 35 mm to 3.5 cm; volume = 378 cm3.
4
Length Width Height Volume

a 5 cm 12 mm 6 mm 3600 mm3

b 12 cm 8 cm 4 mm 38.4 cm3

c 8m 6m 90 cm 43.2 m3

d 1.2 m 60 cm 25 cm 180 000 cm3

5 a volume: 32.256 m3 b 3 × 5 × 2 = 30 m3
6 89.6 kg

F Exercise 18.5
1 a 228 cm2 b 76 cm2 c 160 cm2
2 a 148 m2 b 800 mm2
3 a 55.92 m2 b 2 × 6 × 2 + 2 × 6 × 2 + 2 × 2 × 2 = 56 m2
4 a 1620 mm2 b 16.2 cm2
5 a 18 tins b $152.82

End of unit review


1 a m2 b cm2
2 a 800 b 50 000 c 4.2
3 a area: 30 cm2, perimeter: 22 cm b area: 21 m2, perimeter: 20 m
c area: 400 mm (or 4 cm ), perimeter: 116 mm (or 11.6 cm)
2 2

4 a 4m b 20 m
5 a i 102 cm2 ii 255 mm2 b 46 cm
6 a 144 cm 3
b 180 cm 2

7 S he added the dimensions instead of multiplying; the units should be mm3, not mm;
volume = 1440 mm3.
8 a 108.46 m2 b 2 × 7 × 4 + 2 × 7 × 3 + 2 × 4 × 3 = 122 m2

2 Cambridge Checkpoint Mathematics 7 Copyright Cambridge University Press 2012

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