P = Perimeter
L = Length
W = Width
Perimeter of rectangle = L + L + W + W
or P = 2L + 2W
You know:
P = 36 inches
L = 2W [length is(=) 2 times it's width]
W = ?
P = 2L + 2W
Substitute/plug in what you know, plug in 2W for L since L = 2W
36 = 2(2W) + 2W Simplify
36 = 4W + 2W
36 = 6W Divide 6 on both sides
6 = W Now that you know the width, you can find the length:
L = 2W
L = 2(6)
L = 12
L = 12 in
W = 6 in
PROOF
P = 2(12) + 2(6)
P = 24 + 12
P = 36
