none there is no dirt in a hole
cylinder 18 feet diameter x 1.5 feet deep volume = 381 cubic feet
1.963 cubic feet
There is 98.17477042 cubic feet of dirt in a 5 foot deep hole that is 5 foot across.
None. If it's a hole, then the dirt has been removed.
6,400 ft3
There is no dirt in a hole that is 3 feet deep and six inches in diameter.
none.
None! If there was dirt in it then it wouldn't be a hole.
cylinder 18 feet diameter x 1.5 feet deep volume = 381 cubic feet
1.963 cubic feet
There is 98.17477042 cubic feet of dirt in a 5 foot deep hole that is 5 foot across.
None. If it's a hole, then the dirt has been removed.
6,400 ft3
As it is a hole there is no dirt in it. However, a cylinder of dirt with radius 1.5ft, depth 5ft and a volume of πr2h ~= 35.34 cu ft has been removed.
8 cubic feet.
1 foot by 36 sq feet = 36 cubic feet of dirt is needed
If there is dirt in a hole of the specified dimensions, you weren't very successful at digging the hole.