Cylinders and cubic feet or quarts
by Soil_Soup on 11/18/03 at 19:15:49

I plan on using an auger bit to remove the poor soil then add premium soil to the newly made holes.  The hole will be 3" x 10" and the premium soil will be measured in quarts or cubic feet.  How do I determine the number of bags to purchase for a given number of holes?

Re: Cylinders and cubic feet or quarts
by Robert Fogt on 11/19/03 at 06:04:54

The formula for calculating volume is:
Volume = Area * Height

So, calculate the area of the circle, then multiply it by the depth of the hole.

The formula for calculating the area of a circle is:
Area = Pi * r²
(r being the radius, which is 1/2 the diameter)

The completed formula would then be:
Volume = Pi * r² * Height

You didn't mention if the hole was 3" in diameter and 10" in depth, or the other way around, so I will calculate for both.

For a 3" diameter hole with a 10" depth:
Volume = Pi * (1.5)² * 10 = 70.6858 cubic inches

For a 10" diameter hole with a 3" depth:
Volume = Pi * (5)² * 3 = 235.61945 cubic inches

You can then convert cubic inches to quarts or cubic feet on the volume conversion page.

Re: Cylinders and cubic feet or quarts
by Soil_Soup on 11/19/03 at 08:56:32

Thanks for the quick reply.  I am, however, surprised that reversing the orientation made such a difference.  

For a 3" diameter hole with a 10" depth:
Volume = Pi * (1.5)² * 10 = 70.6858 cubic inches

For a 10" diameter hole with a 3" depth:
Volume = Pi * (5)² * 3 = 235.61945 cubic inches

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