The side length of a square is decreasing at a rate of 2

Last updated: 7/6/2022

The side length of a square is decreasing at a rate of 2 kilometers per hour. At a certain instant, the side length is 9 kilometers. What is the rate of change of the area of the square at that instant (in square kilometers per hour)? A. -81 B. -36 C. -4 D. -324