Question

The perimeter of a rectangle is 108cm. The ration of its length to its width is 7:2 what is the area of the rectangle in cm2?

Answer 1

504 cm²

Explanation:

Let the length and the width of the rectangle be L cm and W cm respectively.

Perimeter= 2(L +W)

2(L +W)= 108

L +W= 108 ÷2

L +W= 54

L= 54 -W -----(1)

`(L)/(W) = (7)/(2)`

Cross multiply:

2L= 7W -----(2)

Substitute (1) into (2):

2(54 -W)= 7W

Expand:

108 -2W= 7W

+2W on both sides:

9W= 108

Divide both sides by 9:

W= 108 ÷9

W= 12

Substitute W= 12 into (1):

L= 54 -12

L= 42

Area of rectangle

= length ×width

= LW

= 42(12)

= 504 cm²