A circular oil spill has area A = pi r^2. At the moment r = 7 meters, the radius is increasing at 0.3 m/min. How fast is the area increasing?
Answer
4.2pi square meters per minute
Reasoning Strategy
Differentiate A = pi r^2 with respect to time, then substitute r and dr/dt.
AI Support Preview
Keep dA/dt and dr/dt distinct before applying the chain rule.