The diameter is given as 28 feet and height is 11 feet.
To find the radius of the feet,
[tex]d=2r[/tex][tex]28=2r[/tex][tex]r=\frac{28}{2}=14[/tex]To determine the volume of cone , use the formula .
[tex]V=\frac{1}{3}\pi(r^2)h[/tex]Substitute the values in the formula.
[tex]V=\frac{1}{3}\times3.14\times14\times14\times11[/tex][tex]V=2256.6ft^3[/tex]Hence the volume of pile is
[tex]V=2256.6ft^3[/tex]