# Math Help - Find the rate of change

1. ## Find the rate of change

Hi,

I'm having problems understanding where to begin with this problem. Could someone here please point me in the right direction?

2. ## Re: Find the rate of change

We are given:

$V=\frac{1}{3}\pi r^2h$

and $h=3r$ so we may write:

$V=\frac{1}{3}\pi r^2(3r)=\pi r^3$

Now, implicitly differentiate with respect to time $t$, then use the values given for $\frac{dr}{dt}$ and $r$ to find $\frac{dV}{dt}$