Calculus: Related rates

okay, some smarty pants explain to me how to do this problem:

Sand is being dumped on a pile in such a way that it always forms a cone whose radius equals its height. If the sand is being dumped at a rate of 10 cubic feet per minute, at what rate is the height of the pile increasing when there is 1000 cubic feet of sand in the pile?

This problem is from Ostebee Zorn Calculus Book, section 4.9 #6.