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 1 : 4. The ratio of the area of J to the area of H is 8 : 9. If the area of G is 75 cm
2, what is the area of the rectangle CDEF?
K |
J |
H |
G |
1x2 |
4x2 |
|
|
|
8x1 |
9x1 |
|
2 u |
8 u |
9 u |
3 u |
Area J is the repeated identity.
LCM of 4 and 8 = 8
Half of the area of the rectangle
= Area K + Area H
= 2 u + 9 u
= 11 u
Area of G
= Half of the area of the rectangle - Area J
= 11 u - 8 u
= 3 u
3 u = 75
1 u = 75 ÷ 3 = 25
Area of the rectangle
= 11 u x 2
= 22 u
= 22 x 25
= 550 cm
2 Answer(s): 550 cm
2