$\textbf{Problem}:$ A square pyramid of side length $100$cm and height of $100$cm is melting at a consistent rate such that all of the ice less than $y$ cm from the surface melts after $y$ hours. (Note the bottom is also melting). What is the rate of change of the volume, when the height is $10$ cm?
So I know $V=s^2\frac{h}{3}$ and the side length equals the height so can I set $s=h$? Then differentiate. I am confused on the rate of decrease of the surface area and how it relates.