How many cubic yards of concrete are needed to make 1200 square concrete posts 9-inches by 9-inches by 6-feet?
(3/4)(3/4)(6) = 3.375 ft^3/post
3.375 ft^3/post * 1200 posts = 4050 ft^3
but 27 ft^3 = 1 yd^3
4050 ft^3 * 1 yd^3/27ft^3 = 150
3.375 ft^3/post * 1200 posts = 4050 ft^3
but 27 ft^3 = 1 yd^3
4050 ft^3 * 1 yd^3/27ft^3 = 150