1.53 cubic yards.
It depends on how deep it is. If it is 6 inches deep, you will need 77 yards.
It would be helpful to have units of measurement in the equation. However, pouring a slab I'll presume your measurements are feet x feet x inches. The volume of this slab is 55 x 15 x 0.5 (6 inches is 0.5 ft) = 412.5 cubic feet 1 yard of cement (more likely concrete as a cement slab will crumble under load) is equal to 27 cu.ft. So, 412.5 cu.ft. needed / 27 cu. ft. / cu. yd. = 15.2777...cu. yards. you will need to order 15.27777...cu. yards, as a yard isn't sold in this decimal you will need to order 15 1/2 yards of concrete to pour your slab.
To calculate the volume of the slab in cubic yards, first find the volume in cubic feet by multiplying the dimensions: 3 ft x 10 ft x 4 ft = 120 cubic feet. Since there are 27 cubic feet in a cubic yard, divide 120 by 27 to convert to cubic yards: 120 ÷ 27 ≈ 4.44 cubic yards. Therefore, you will need approximately 4.44 cubic yards of cement for the slab.
If the slab is the standard 4" deep, you will need at least 8.89 cubic yards.
4.074 cubic yards for every foot the slab is thick.
You will need 6.17 cubic yards of cement.
8.64 cubic yards of cement.
You will need 27.6 cubic yards of cement.
1.85 cubic yards.
0.86 cubic yards is needed.
A 40x60x6in slab requires 44.44 cubic yards of cement.
3.95 cubic yards of cement are needed for a slab that size.
A 16' x 8' by 4" slab requires 3.56 cubic yards of cement.
You'll need 1 cubic yard.
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.
40" x 40" x 3" requires 0.1 cubic yards of cement. If you mean 40 x 40 feet, you will need 14.81 cubic yards of cement.