Cambridge International Mathematics

Mensuration (length and area) (Chapter 9) 199

a Area

=^12 base£height

=^12 £ 12 £ 5

=30m^2

b Area

=base£height

=10£ 5

=50cm^2

c Area

=

μ

a+b

2

¶

£h

=

μ

11 + 16

2

¶

£ 4

=54m^2

Example 6 Self Tutor

Find the green

shaded area:

ab

a

Area=area of rectangle+area of triangle

=10£4+^12 £ 6 £ 5

=40+15

=55cm^2

b Area=area large rectangle¡area small rectangle

=12£ 6 ¡ 4 £ 2

=64m^2

EXERCISE 9C.2

1 Find the area of the shaded region:

abc

de f

gh i

4cm 9cm

10 cm

4m

2m

12 m

6m

4cm

6cm

4cm

5cm

4cm

10 cm

We divide the figure into a rectangle and a triangle as shown below:

14 m

6m

6cm

13 cm

5cm

6cm 9cm

5cm

5cm

8cm

25 m

15 m

12 m 4cm

7cm

5cm 6.2 cm

3.8 cm

5cm

IGCSE01

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Y:\HAESE\IGCSE01\IG01_09\199IGCSE01_09.CDR Tuesday, 23 September 2008 11:01:30 AM PETER