Question 1013620
We have
W = L - 4
and
W^2 + L^2 = 20^2
Now substitute and get
(L-4)^2 + L^2 = 20^2
L^2 - 8L + 16 + L^2 = 400
2L^2 - 8L - 384 = 0
L^2 - 4L - 192 = 0
(L - 16)(L + 12) = 0
L = 16 so that
W = 12 inches