word problem find the length and width

Question

A rectangle is 3 km longer than it is wide. Find the dimensions of the rectangle if its area is 238 sq-km.

Answer 1

238 = LW = (W+3)W = W^2 + 3W

W^2 + 3W = 238

W^2 + 3W + 9/4 = 238 + 9/4

(W+3/2)^2 = 961/4

W+ 3/2 =31/2

W =28/2 = 14 km wide

L =3+W = 17 km long