15'x37'x4" requires 6.85 cubic yards.
28
You will need 27.6 cubic yards of cement.
Thickness? Do you mean cement or concrete - cement is the binder/adhesive in the concrete.
A minimum of 5.93 cubic yards is needed.
14.81 cubic yards.
0.86 cubic yards is needed.
3.95 cubic yards of cement are needed for a slab that size.
25
18.52 cubic yards are needed.
1.85 cubic yards of cement.
8.64 cubic yards of cement.
1.5 cubic yards of cement are needed for an 11' x 11' x 4" slab.