For a 4-inch slab with a radius of 10 feet, how many cubic yards of concrete are required?

For a 4-inch slab with a radius of 10 feet, how many cubic yards of concrete are required?

• A. 3.87 cu yd
• B. 2.5 cu yd
• C. 3.0 cu yd
• D. 4.5 cu yd

Answer: (A)

The main idea is volume of a circular slab treated as a cylinder: V = π r^2 h. With a radius of 10 feet and a thickness of 4 inches, convert height to feet: 4 inches = 1/3 foot. So V = π × (10 ft)^2 × (1/3 ft) = 100π/3 ≈ 104.72 cubic feet.Convert to cubic yards (1 yd^3 = 27 ft^3): 104.72 / 27 ≈ 3.88 yd^3. This matches about 3.87 cubic yards, which is why that option is the correct choice. If you see a different number, it usually comes from not converting the thickness to feet or from mixing up the cubic-foot to cubic-yard conversion.

The main idea is volume of a circular slab treated as a cylinder: V = π r^2 h. With a radius of 10 feet and a thickness of 4 inches, convert height to feet: 4 inches = 1/3 foot. So V = π × (10 ft)^2 × (1/3 ft) = 100π/3 ≈ 104.72 cubic feet.Convert to cubic yards (1 yd^3 = 27 ft^3): 104.72 / 27 ≈ 3.88 yd^3. This matches about 3.87 cubic yards, which is why that option is the correct choice. If you see a different number, it usually comes from not converting the thickness to feet or from mixing up the cubic-foot to cubic-yard conversion.