1. The problem statement, all variables and given/known data Water is being drained from a container which has the shape of an inverted right circular cone. The container has a radius of 5.00 inches at the top and a height of 7.00 inches. At the instant when the water in the container is 4.00 inches deep, the surface level is falling at a rate of 0.7 in/sec. Find the rate at which water is being drained from the container. 2. Relevant equations v=1/3 pi r^2 h 3. The attempt at a solution The values I came up with are as follows. h=4 (of water level) r=2.86 (of water level found using equal triangles) dV/dt= what I am solving for dh/dt = -0.7 Whenever I take the derivative of the volume equation I end up with a dr/dt that I have no idea what to do with. Am I just doing it wrong and getting the dr/dt when I shouldn't? I also noticed in a few google results they'd used similar triangles to get r in terms of h. But whenever I do that, I get an actual value for r and the h goes away. Perhaps this is where I am messing up?