Hi Steve,

The shape of each pile is approximately a cone and you can use the expression for the volume of a cone to find its volume. We have done precisely that in our response to an earlier question. There is however an easier procedure.

The volume of a cone of radius $r$ units and height $h$ units is

\[\pi \; r^2 h \mbox{ cubic units.}\]

The volume of a cylinder with the same radius and height is

\[\frac13 \pi\; r^2 h \mbox{ cubic units.}\]

Hence the volume of the cone is one third the volume of the cylinder. My suggestion is that for each of your plies you use our volume calculator at

mathcentral.uregina.ca/volume_calculator

to calculate the volume of the cylinder with the dimensions you supplied and then divide by 3 to find the volume of the conical pile. You can use the example in the first paragraph of my response to check that you are using the procedure correctly.

Harley