Please help me find the answer

Question

The radius r of a circle is increasing at a rate of 3 centimeters per minute. Find the rate of change of the area when r = 38 centimeters.

Answer? cm^2/min

Answer 1

The radius r of a circle is increasing at a rate of 3 centimeters per minute. Find the rate of change of the area when r= 38 centimeters.

So given dr/dt=3 cm/min

dA/dt= x cm²/min

A=∏*r²

Take the derivative with respect to t for all variables

dA/dt=∏*2 (38) *dr/dt

= 76∏* 3

= 716.283 cm²/min

Answer is 716.283 cm²/min