The length of a rectangle is 6 yards longer than its width. If the perimeter of the rectangle is 36 yards , find its area.
p = 2(l+w)
l = w + 6
so p = 2(w + 6 + w)
36 = 2(2w + 6)
18 = 2w + 6
9 = w + 3
6 = w
w = 6, l = 6+6 = 12
a = lw = 6 * 12 = 72 sq yards