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15 Area, perimeter and volume

Use this brief summary to remind yourself of the work you have Key words
done on area, perimeter and volume.
Make sure you learn and
understand these key words:
hectare
prism
cross-section
To work out the area (A) To work out the area (A)
and circumference (C) of of a triangle use this
a circle use these formulae: formula:
C = πd or C = 2πr h
1
A = πr 2 A = bh b
d 2
r

To work out the area (A) of a To work out the area (A) of
parallelogram use this formula: a trapezium use this formula:
a
1
A = bh h A = × (a + b) × h
2 h
b
b

!e lengths in this diagram are in centimetres. 8
Find the area of each part.
3 3

!e area of the square is 8 × 8 = 64 cm².
3 5

5 5

5 3

!e parts are rearranged to make a rectangle. 8 5

!e area of the rectangle is 5 × 13 = 65 cm².
3
It should be 64 cm²! 5 5
Where is the extra 1 cm²? 3

5 8

In this unit you will convert metric units of area and of volume. You will also solve problems involving
the circumference and area of circles, as well as working with right-angled prisms and cylinders.

15 Area, perimeter and volume 15 Area, perimeter and volume 141