How many yards of concrete does it take to pour a round 12 foot by 3 inches thick?

Answer 1

First you have to figure out the area of a the circle using the (pie x r2 )Formula. 12 feet is your diameter, So the radius or r = 6 Pie = 3.14 r2 =36. (3.14 x 36 = 113.04) Now you have to figure out the volume of the slab. volume = area x depth . Seeing we are working with square footage we have to convert the 3 inches to feet. 12 inches in a foot. Divide 3 BY 12. (3 / 12 = .25 ) Now multiply by the area (113.04 X .25 = 28.26) 28.26 cubic ft. is the volume of the slab. To convert to cubic yards you divide by 27. A cubic yard is 3 feet wide 3 feet long and 3 feet high. So (3 x 3 x 3 = 27). Now take the volume in cubic feet 28.26 divided by 27. (28.26 / 27 = 1.046) You need 1.046 cubic yards of concrete to pour a slab 12 feet in diameter 3 inches thick. This is for an exact 3 inch thick by 12 foot diameter slab. If you order from most ready mix concrete firms they'll probably charge for and send 1.25 cubic yards to make sure you have enough.