The sides of a square increase in length at a rate of 4 m/sec. a. At what rate is the area of the square changing when the sides are 12 m long? b. At what rate is the area of the square changing when the sides are 20 m long? a. Write an equation relating the area of a square, A, and the side length of the square, s. Differentiate both sides of the equation with respect to t. dA ds dt dt The area of the square is changing at a rate of when the sides are 12 m long. b. The area of the square is changing at a rate of when the sides are 20 m long