How many gallons can a 12-inch diameter, 500-foot long pipe hold?

How many gallons can a 12-inch diameter, 500-foot long pipe hold?

• A. 1,936 gal
• B. 2,936 gal
• C. 3,936 gal
• D. 4,936 gal

Answer: (B)

Volume of a cylinder is found with V = π r^2 h. The pipe has a 12-inch diameter, so the radius is 6 inches, which is 0.5 feet. The length (height) is 500 feet. So V = π × (0.5)^2 × 500 = π × 0.25 × 500 = 125π cubic feet ≈ 392.7 ft^3. Converting to gallons (1 ft^3 ≈ 7.4805 gal) gives 392.7 × 7.4805 ≈ 2,936 gallons. So the pipe can hold about 2,936 gallons.

Volume of a cylinder is found with V = π r^2 h. The pipe has a 12-inch diameter, so the radius is 6 inches, which is 0.5 feet. The length (height) is 500 feet. So V = π × (0.5)^2 × 500 = π × 0.25 × 500 = 125π cubic feet ≈ 392.7 ft^3. Converting to gallons (1 ft^3 ≈ 7.4805 gal) gives 392.7 × 7.4805 ≈ 2,936 gallons. So the pipe can hold about 2,936 gallons.