geometry
posted by joe .
concrete can be purchased by the cubic yard. how much will it cost to pour a slab 17 feet by 17 feet by 2 inches for a patio of the concrete cost $ 40 per cubic yard

17 * 17 * 1/6 = 48.167 ft^3
1 yd^3 = 3*3*3 = 27 ft^3
48.167 ft^3/27 ft^3/yd^3 = 1.784 yd^3
1.784 yd^3 * $ 40/ yd^3 = $ 71.36
by the way, concrete people refer to a cubic yard as a "yard".
They are not likely to send a truck with 1.784 yards, so you will pay for 2 yards or $ 80