OK, here it goes...
Coverage for bulk material (gravel, soil, etc.)...
One cubic yard of material will cover...
27 square feet - 12" deep
54 square feet - 6" deep
81 square feet - 4" deep
108 square feet - 3" deep
162 square feet - 2" deep
324 square feet - 1" deep
The formula is: Depth of material in inches divided into 12...Take that number and multiply it by 27...this will give you the number of square feet that one cubic yard of material will cover at that depth.
Flagstone/Stepstone coverages per ton (apprx.):
1" minus thickness - 175 - 200 sqft
1-2" thickness - 100-125 sqft
2-3" thickness - 70-90 sqft
Building Stone coverages per ton (apprx):
2-3" bed depth - 50-60 sqft (face)
3-4" bed depth - 40-50 sqft (face)
4-6" bed depth - 30-40 sqft (face)
6-8" bed depth - 25-30 sqft (face)
8-12" bed depth - 15-25 sqft (face)
Note: bed depth refers to the depth of stone from the face to the back when it is laid
Surface area of a CIRCLE:
multiply 3.14 x the radius squared
Pond Volume:
Area x Average Depth + Cubic Feet x 7.5 gallons/cu ft.