The perimeter of a parallelogram is 72 m. The width of the parallelogram is 4 m less than its length. Find the length and the width of the parallelogram.

Let L = length and W = width

(1) Perimeter = 2 (L + W) = 72 m (given)

W = L - 4 (given). Plug in the value of W in (1)

Perimeter = 2[L + (L-4) ] = 72

Perimeter = 2[2L-4) ] = 72

Perimeter = 4L - 8 = 72

4L = 80 and L = 20, and W = 16