What is the volume of a cylinder with a diameter of 3 feet and length 12 feet?

What is the volume of a cylinder with a diameter of 3 feet and length 12 feet?

• A. 90.00 cubic feet
• B. 84.78 cubic feet
• C. 78.50 cubic feet
• D. 82.40 cubic feet

Answer: (B)

The volume of a cylinder is found with V = π r^2 h, where r is the radius of the circular base and h is the height (length) of the cylinder. The diameter is 3 ft, so the radius is 1.5 ft. Squaring the radius gives 2.25, and multiplying by the length 12 ft yields 27. So V = π × 27, which is 27π cubic feet. Using π ≈ 3.14, the volume is 27 × 3.14 = 84.78 cubic feet. If you use a more exact π, you’d get about 84.82 cubic feet. The option around 84.78 cubic feet matches the common π approximation used in many problems, making it the best choice.

The volume of a cylinder is found with V = π r^2 h, where r is the radius of the circular base and h is the height (length) of the cylinder. The diameter is 3 ft, so the radius is 1.5 ft. Squaring the radius gives 2.25, and multiplying by the length 12 ft yields 27. So V = π × 27, which is 27π cubic feet.

Using π ≈ 3.14, the volume is 27 × 3.14 = 84.78 cubic feet. If you use a more exact π, you’d get about 84.82 cubic feet. The option around 84.78 cubic feet matches the common π approximation used in many problems, making it the best choice.