The figure, not drawn to scale, shows a rectangle, CDEF, which is divided in 4 parts, G, H, J, and K. The ratio of the area of K to the area of J is 2 : 7. The ratio of the area of J to the area of H is 4 : 5. If the area of G is 300 cm
2, what is the area of the rectangle CDEF?
| K |
J |
H |
G |
| 2x4 |
7x4 |
|
|
| |
4x7 |
5x7 |
|
| 8 u |
28 u |
35 u |
15 u |
Area J is the repeated identity.
LCM of 7 and 4 = 28
Half of the area of the rectangle
= Area K + Area H
= 8 u + 35 u
= 43 u
Area of G
= Half of the area of the rectangle - Area J
= 43 u - 28 u
= 15 u
15 u = 300
1 u = 300 ÷ 15 = 20
Area of the rectangle
= 43 u x 2
= 86 u
= 86 x 20
= 1720 cm
2 Answer(s): 1720 cm
2 
