calculus
posted by John .
Suppose that the radius r of a right circular cone of fixed height h = 20 cm is increasing at a rate 4 cm/s. How fast is the volume increasing when r = 10? Give your answer correct to two decimal places.

V = (pi/3) h r^2
dV/dt = 2*(pi/3)*h*r*(dr/dt)
You have all the terms you need to calculate that.