Page 170 - MAT KS3 Y8 Cambridge CheckPoint

17.2 The areas of a parallelogram and trapezium

Exercise 17.2

1 Work out the area of these parallelograms.
a b c
3 cm 15 mm 4.2 cm

6 cm
26 cm 7.3 cm
2 Work out the area of each trapezium.
a 4 cm b 3 cm c 8.2 cm

5 cm 7 cm 3.6 cm
8 cm 6.4 cm
6 cm
3 This is part of Zalika’s
homework. Question What is the difference in the areas of these
a Explain the mistake two shapes?
that Zalika has made. A 12 mm B 6 cm
b Work out the correct 9 cm
answer for her. 15 mm
10 cm
Answer Area A = b × h = 15 × 12 = 180

Area B = 1 × (a + b) × h = 1 × (6 + 10) × 9
2 2
= 1 × 16 × 9 = 72
2
Difference = 180 – 72 = 108

4 Here are four shapes A, B, C and D.
A 4.5 cm B C D
3.7 cm 2.9 cm 2.7 cm

3.8 cm
4.2 cm 3.4 cm 8.2 cm
5.4 cm
Here are five area cards.
i ii iii iv v
9.86 cm 2 18.81 cm 2 24.48 cm 2 15.54 cm 2 11.07 cm 2

a Using only estimation, match each shape to its area card.
b Use a calculator to check that you have matched the shapes and the area cards correctly.
c Sketch a shape that has an area equal to the area on the card you haven’t matched.
2
5 A parallelogram has an area of 832 mm .
It has a perpendicular height of 2.6 cm.
What is the length of the base of the parallelogram?
2
6 A trapezium has an area of 1500 mm .
The lengths of its parallel sides are 4.8 cm and 5.2 cm.
What is the perpendicular height of the trapezium?
168 17 Area, perimeter and volume
168