I have to answer this question: Before a gasoline-powered engine is started, water must be drained out of the bottom of the tank. Suppose the tank is a right circular cylinder on its side with length 12 feet and a radius of 4 feet. If the water level is 18 inches above the lowest part of the tank, determine how much water must be drained from the tank. Round your final answer to the nearest tenth.
I know this is a volume application, which will use triple integrals. I also get understand that as it's laying on its side, it's centered on the y-axis.
I just don't know how to start the problem.