The figure, not drawn to scale, is made up of 2 triangles, BHJ and FHJ. BC is
12 of FG. DE is
56 of BC and the difference between FG and DE is 21 cm. Given that JH = 15 cm, find the area of the entire figure.
BC |
FG |
DE |
1x6 |
2x6 |
|
6x1 |
|
5x1 |
6 u |
12 u |
5 u |
7 u = 21 cm
1 u = 21 ÷ 7 = 3 cm
Length of BC
= 6 u
= 6 x 3
= 18 cm
Length of FG
= 12 u
= 12 x 3
= 36 cm
Length of DE
= 5 u
= 5 x 3
= 15 cm
Area of Triangle BHJ
=
12 x 15 x 18
= 135 cm
2 Area of Triangle FJH
=
12 x 15 x 36
= 270 cm
2 Area of Triangle DJH
=
12 x 15 x 15
= 112.5 cm
2 Area of the figure
= 135 + 270 - 112.5
= 292.5 cm
2 Answer(s): 292.5 cm
2