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 19 mlong?

b. At what rate is the area of the square changing when the sides are 30 mlong?

a. The area of the square is changing at a rate of ? when the sides are 19 m long.

b. The area of the square is changing at a rate of ? when the sides are 30 m long.