What is the volume of a cylinder with radius 3 and height 7?

• A. 21π
• B. 9π
• C. 63π
• D. 49π

Answer: (C)

The volume of a cylinder is found by multiplying the area of the circular base by the height. The base area is πr^2, and with radius 3 this gives π(3)^2 = 9π. Multiply by the height 7: 9π × 7 = 63π. So the volume is 63π cubic units. The other options would result from mixing up the radius squared and the height (for example, using just the base area 9π, or using 7^2 for the radius, which isn’t the given radius).