



 
Hi Wesley, There is an error in your "81 slabs" calculation and also you don't need to use cubic yards at all. 81 slabs forms a square which is 9 slabs by 9 slabs. Each slab is 4" long so 9 slabs is 4 × 9 = 36 inches which is 3 feet. Hence 81 slabs forms a square that is 3 feet by 3 feet. Hence the 81 slab square which is 2" deep has a volume of 3' × 3' × 1/6' = 1.5 cubic feet. How many cubic feet are in 810 slabs? Each bag of cement makes approximately half a cubic foot so how many bags are needed? I hope this helps,  


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