1. A rectangle has a constant area of 200 square meters and its length L is increasing at the rate of 4 meters per second. Find the width W at the instant the width is decreasing at the rate of 0.5 meters per second. 2. Know: dL/dt= 4 m/s, dW/dt=.5 m/s Want: W 3. LW=A. Then DL/dt * DW/dt = 200 m^2. How do you get W from this? I have some other questions too. Related rates are hard.