Question

A 4-inch-thick concrete slab is being poured for a circular patio 10 feet in diameter. Concrete costs $50 per cubic yard. Find the cost of the concerte, to the nearest cent. Show how you come to your answer.

Answer 1

1 cubic yard is 27 cubic feet. SO, concrete costs about $1.85 per cubic foot.

A 4" slab is 1/3 foot thick. So, the volume of concrete is the area of the patio, times its thickness, all in feet:

v = pi * 25 * 1/3 = 26.18 cubic feet.

cost = 26.18 * 1.85 = $48.43

Makes sense, since it's almost 1 cubic yard.