Question

A rectangle's width is one-fifth it's length, and it's perimeter is 180m. Find the dimensions of the rectangle. The length is M and the width is m

Answer 1

P = 2(L + W)
P = 180
W = 1/5L

180 = 2(L + 1/5L)
180 = 2(6/5L)
180 = 12/5L
180 / (12/5) = L
180 * 5/12 = L
75 = L <=== length is 75m

W = 1/5L
W = 1/5(75)
W = 75/5
W = 15 <=== width is 15m

Answer 2

12L=720 
L=720/12 
L=60 ANS. FOR THE LENGTH. 
W=60/5=12 ANS. FOR THE WIDTH. 
Evidence: 
144=2*60+2*12 
144=120+24 
144=144