Area of Plane Shapes

Area of Compound Shapes

8 m

2 m

2 m

5 m2 m

2 m

Not to scale

4 m

3 m

?

?

16 m2

20 m26 m2

Area = 16 + 20 + 6 = 42 m2

Area = ½ x 8 x 9

= 36 cm2

Area = ½ x 10 x 12

= 60 cm2

Area = ½ x 14 x 16

= 112 cm2

Area = ½ x 3.2 x 4.5

= 7.2 m2

Find the area of the following triangles.

8 cm 10 cm

14 cm

12 cm9 cm 16

cm

3.2 m

4.5 m

7 mm

5 mm

Area = ½ x 7 x 5

= 17.5 mm2

8 cm

14 mm

1.5 m

12 cm

5 mm

2.1 m

Find the area of each parallelogram below.1

2

3Area = 8 x 12

= 96 cm2

Area = 14 x 5

= 70 mm2

Area = 1.5 x 2.1

= 3.15 m2

The Area of a Trapezium Area = ½ the sum of the parallel sides x the perpendicular height

A = ½(a + b)h

a

b

h½ah

½bhArea = ½ah + ½bh = ½h(a + b)

= ½(a + b)h

Area = ½ (8 + 12) x 9

= ½ x 20 x 9

= 90 cm2

Area = ½(7 + 5) x 6

= ½ x 12 x 6

= 36 cm2

Find the area of each trapezium

1

8 cm

12 cm

9 cm

25 cm

7 cm

6 cm

3

5 cm

3.9 cm

7.1 cm

Area = ½(3.9 + 7.1) x 5

= ½ x 11 x 5

= 27.5 cm2