The rectangle is divided into four parts J, K, L and M. The ratio of Part J to Part K is 6 : 1 and the ratio of Part K to Part L is 3 : 2.
- Find the ratio of Part J to Part K to Part L.
- Given that Part M is 19 cm2 , find the area of the rectangle.
(a)
| J |
K |
L |
M |
| 6x3 |
1x3 |
|
|
| |
3x1 |
2x1 |
|
| 18 u |
3 u |
2 u |
19 cm2 |
Part K is the repeated identity.
LCM of 1 and 3 = 3
Part J : Part K : Part L = 18 : 3 : 2
(b)
Part J + Part K = Half of the rectangle
Part L + Part M = Half of the rectangle
Part J + Part K and Part L + Part M are equal.
Part J + Part K = Part L + Part M
18 u + 3 u = 2 u + 19
18 u + 3 u - 2 u = 19
19 u = 19
1 u = 19 ÷ 19 = 1
Area of the rectangle
= 2 x (2 u + 19)
= 2 x (2 x 1 + 19)
= 2 x (2 + 19)
= 2 x 21
= 42 cm
2 Answer(s): (a) 18 : 3 : 2; (b) 42 cm
2 
