The figure, not drawn to scale, is made up of 2 triangles, CJK and GJK. CD is
12 of GH. EF is
78 of CD and the difference between GH and EF is 81 cm. Given that KJ = 21 cm, find the area of the entire figure.
CD |
GH |
EF |
1x8 |
2x8 |
|
8x1 |
|
7x1 |
8 u |
16 u |
7 u |
9 u = 81 cm
1 u = 81 ÷ 9 = 9 cm
Length of CD
= 8 u
= 8 x 9
= 72 cm
Length of GH
= 16 u
= 16 x 9
= 144 cm
Length of EF
= 7 u
= 7 x 9
= 63 cm
Area of Triangle CJK
=
12 x 21 x 72
= 756 cm
2 Area of Triangle GKJ
=
12 x 21 x 144
= 1512 cm
2 Area of Triangle EKJ
=
12 x 21 x 63
= 661.5 cm
2 Area of the figure
= 756 + 1512 - 661.5
= 1606.5 cm
2 Answer(s): 1606.5 cm
2