Question

The length of a rectangle is 4 feet more than the width. If the perimeter is 20 ft. What is the length of the rectangle?

Answer 1

Perimeter:  P = 2L + 2W.  In this problem L = W + 4 or W = L - 4.  We want L, so let's eliminate W:

P = 2L + 2(L - 4) = 20 (all measurements in feet)

Simplifying,

     2L + 2L - 8 = 20, or 4L = 28 ft.  Thus, L = 7 ft.

The rectangle is 7 ft long.