how do you find the perimeter of a rectangle

Question

Find in the perimeter of a rectangle if the area is 40 feet 

Answer 1

Area = A = LW = length times width

Perimeter = P = 2L +2W

if A=40, then L=40/W and

P =2(40/W)+2W = 80/W +2W

or P = 80/L +2L

Usually this type of problem has some additional information about L and W, such as L=2W, length is twice the width. then you can solve for a unique value for the perimeter

40 = LW = 2WW = 2W^2

W^2 =40/20 = 20

W= sqr20

L = 2sqr20

P=2(L+W) = 2(3sqr20) = 6sqr20