"Water is being poured into a conical vessel of semi vertical angle of 30 degrees at the rate of 100Pi cm cubed per minute. find the rate at which the depth pf water is increasing when the water is 5cm deep."

I can't really seem to get my head around this question.

As far as I can make out it involves a little bit of trigonometery which I'm terrible at. The only thing I can make out so far is that I'm looking for dV/dT.

All help really appreciated!

The question is worth quiet a bit of my exam. :o