Volume of a cylinder equals which expression?

Volume of a cylinder equals which expression?

• A. 2πrh
• B. πr^2
• C. πr^2h
• D. 2πr h

Answer: (C)

Volume is found by multiplying the base area by the height. For a cylinder, the base is a circle with area π r^2, and stacking thin disks of thickness dh across the height h adds up to π r^2 h. So the volume is π r^2 h. The other expressions don’t measure volume: 2π r h is the lateral surface area of the curved side, and π r^2 is just the area of the base.

Volume is found by multiplying the base area by the height. For a cylinder, the base is a circle with area π r^2, and stacking thin disks of thickness dh across the height h adds up to π r^2 h. So the volume is π r^2 h. The other expressions don’t measure volume: 2π r h is the lateral surface area of the curved side, and π r^2 is just the area of the base.