No dirt because its a hole
There is no dirt in a hole that is 3 feet deep and six inches in diameter.
If applied 1 foot deep it will cover 108 square feet. If applied 6 inches deep it will cover 216 square feet. It all depends on how thick you apply it.
none there is no dirt in a hole
You are mixing volume (square yard) and area (length x width). How deep do you want the dirt? One foot deep you need about 80 square yards of dirt.
6 cubic yards of dirt will cover 70 sq ft ... 2 ft 3 3/4 inches deep
None. There is nothing in a hole.
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.
None! If there was dirt in it then it wouldn't be a hole.