How much will it cost to pour a circular slab 18 ft in diameter by 3 in. For a patio if the concrete costs $40.00 per cubic yard?

A circular concrete slab is a cylinder. Vol = pi%2Ar%5E2%2Ah
in this cylinder:
r = 18%2F2 = 9 ft
h = 3%2F12 = .25 ft
:

Find the volume in cu/ft:
V = pi%2A9%5E2%2A.25
V = 63.61725 cu/ft
:
Change to cubic yds; (1 cu/yd = 27 cu/ft) and multiply by $40:
Cost = 63.61725%2F27 * 40
Cost = $94.25

In practical terms , they may require you to buy 3 cu/yds , which is $120

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