One "yard" of dirt (meaning one cubic yard) contains 46,656 cubic inches. Spread 8 inches thick this will cover 5832 square inches or 40.5 square feet.
An answer is impossible because there are no cubic units within a circle but only square units
What you have there isn't actually a circle, but a stubby pillbox of a "cylinder".Volume of a cylinder = (pi) (R2) (H) = (pi) (15.5)2 (2) = 1,509.54 cubic inches (rounded)
803.84 is the volume in cubic ft when using 3.14 as pi.
5inches
2560 sq feet 2 inches thick
1 cubic yard/(1/9 of a yard) = 9 square yards.
A cubic yard is 46,656 cubic inches. Spread to a thicknes of 5 inches, a cubic yard of concrete covers 9332.1 square inches, which is 64.8 square feet.
It depends how thick the gravel is being laid - at 4 inches thick, a cubic yard will cover 81 square feet.
To cover 300 square feet 4 inches thick, you would need approximately 3 cubic yards of gravel.
39.1116 cubic yards
I think you mean 6 inches thick, not 6 feet thick. You would need 200 cubic feet, or 7.4 cubic yards.