A cylindrical can hold 460 cubic centimeters of soup.

Find the dimensions of the soup can that uses the least amount of material.

I know that v=pi*(r^2)h and I have to optimize that by taking the derivative and setting equal to zero, but I'm not sure how to get h in terms of r. I had h=460/pi(r^2), but when I solved the problem it didn't turn out right. Maybe I'm doing something wrong?