This depends on the slab thickness required in your area. A six-inch slab would give this calculation: 13.3 yd x 20 yd x 1/6 yd = about 45 cubic yards. Single story residences on stable compacted ground are allowed to be as thin as 4 inches in many areas, which would require only 30 cubic yards.
A 40x60x6in slab requires 44.44 cubic yards of cement.
A 40'x40'x6" slab requires 29.63 cubic yards of cement.
9' by 18' by 4" thick requires at least two cubic yards.
25 Yards of concrete
37.03 yards
3.95 cubic yards of cement are needed for a slab that size.
You will need 27.6 cubic yards of cement.
A minimum of 5.93 cubic yards is needed.
14.81 cubic yards.
0.86 cubic yards is needed.
1.5 cubic yards of cement are needed for an 11' x 11' x 4" slab.
A 40x60x6in slab requires 44.44 cubic yards of cement.
A 16' x 8' by 4" slab requires 3.56 cubic yards of cement.
8.64 cubic yards of cement.
About 24 cubic yards of cement is required for a slab that size.
A 40'x40'x6" slab requires 29.63 cubic yards of cement.
You will need 6.17 cubic yards of cement.