Question: how do you find the length and width of a rectangle with the perimeter?
Answer: Finding Length and Width When You Know Area and Perimeter If you happen to know the distance around the rectangle, which is its perimeter, you can solve a pair of equations for L and W. The first equation is that for area, A = L ⋅ W, and the second is that for perimeter, P = 2L + 2W.