If x is the length of one side of the painting what equation can you set up to find the length of a side?

Answer: This equation has 2 solutions, namely x = ±√400 = + 20 or - 20

The negative solution does not make sense because a length cannot be less than 0.

The total length needed to go around the painting is the perimeter of the square, which is

P = 4*x = 4*20 = 80 inches