The figure, not drawn to scale, shows a rectangle, BCDE, which is divided in 4 parts, F, G, H, and J. The ratio of the area of J to the area of H is 1 : 4. The ratio of the area of H to the area of G is 5 : 7. If the area of F is 351 cm
2, what is the area of the rectangle BCDE?
J |
H |
G |
F |
1x5 |
4x5 |
|
|
|
5x4 |
7x4 |
|
5 u |
20 u |
28 u |
13 u |
Area H is the repeated identity.
LCM of 4 and 5 = 20
Half of the area of the rectangle
= Area J + Area G
= 5 u + 28 u
= 33 u
Area of F
= Half of the area of the rectangle - Area H
= 33 u - 20 u
= 13 u
13 u = 351
1 u = 351 ÷ 13 = 27
Area of the rectangle
= 33 u x 2
= 66 u
= 66 x 27
= 1782 cm
2 Answer(s): 1782 cm
2