A cylinder has a radius of 5 centimeters and a height of 12 centimeters. What would the height of a cone need to be if it is the same volume and radius?

1 answer

well, you need

1/3 pi(5^2)h = pi(5^2)(12)
1/3 h = 12
h = 36

This should be clear since the volume of a cone is 1/3 the volume of an equivalent cylinder. So, if you want the cone of the same radius to have the volume of a cylinder, it must be 3 times as tall.