tan(a)= opposite/adjacent Here, a is 53 degrees, opposite is the long side of the playground (400 feet), and adjacent is the short side of the playground (unknown). tan(53 degrees)=400/x x=400/tan(53 degrees) x=301.4 feet The perimeter is twice the length of the short side plus twice the length of the long side. p=2*400+2*301.4 Perimeter is 1402.8 feet