Question

The length of a rectangle is four times its width. If the area is 400 cm squared, find its perimeter

Answer 1

A = L * W
A = 400
L = 4W

400 = 4W * W
400 = 4W^2
400/4 = W^2
100 = W^2
sqrt 100 = W
10 = W.....width is 10 cm

L = 4W
L = 4(10)
L = 40...length is 40 cm

P = 2(L + W)
P = 2(10 + 40)
P = 2(50)
P = 100 <=== perimeter is 100 cm