I like to think of the volume of any right angled (meaning the sides go straight up rather than slanted up) solid geometric shape in this way: You have a flat two dimensional shape - in this case a circle. Two dimensions have area. When we imagine raising this base to some height, we can see it as creating a three-dimensional shape that has volume. So the measure of the volume is the original area of the base, times the height to which it was raised. I think that visually picturing this would make it easier to remember, as opposed to having to memorize yet another abstract formula.