What is the internal surface area value of the cylindrical tank with diameter 65 ft and height 24 ft?

What is the internal surface area value of the cylindrical tank with diameter 65 ft and height 24 ft?

• A. 11,531.65 ft^2
• B. 10,000 ft^2
• C. 12,000 ft^2
• D. 9,500 ft^2

Answer: (A)

Internal surface area of a closed cylinder comes from the curved side plus both circular ends. So calculate the radius from the diameter: r = 65/2 = 32.5 ft, height h = 24 ft. Curved surface area = 2πrh = 2π × 32.5 × 24 = 1560π ft^2. End caps area = 2πr^2 = 2π × (32.5)^2 = 2112.5π ft^2. Total internal surface area = 1560π + 2112.5π = 3672.5π ft^2 ≈ 1,152.5 × π ≈ 11,537 ft^2. The closest option is about 11,531.65 ft^2.

Internal surface area of a closed cylinder comes from the curved side plus both circular ends. So calculate the radius from the diameter: r = 65/2 = 32.5 ft, height h = 24 ft.

Curved surface area = 2πrh = 2π × 32.5 × 24 = 1560π ft^2.

End caps area = 2πr^2 = 2π × (32.5)^2 = 2112.5π ft^2.

Total internal surface area = 1560π + 2112.5π = 3672.5π ft^2 ≈ 1,152.5 × π ≈ 11,537 ft^2.

The closest option is about 11,531.65 ft^2.