to find the volume of a sphere, use the formula 4/3*pi*radius cubed. the radius of this circle is 6 (half diameter) so use 4/3*pi*6 cubed, which is 4/3*pi*216. multiply by pi to get 678.58*4/3 is the volume. multiply by 4/3 to get about 904.78 inches cubed as the volume. so about 904.78 cubic inches of air.
