The volume of a cylinder is:
[tex]V=\pi r^2h[/tex]
Where:
r is the radius
h is the height
You have the diameter on the base, you use the diameter to find the radius, as the diameter is:
[tex]d=2r[/tex]
Then, the radius is:
[tex]r=\frac{d}{2}[/tex]
d=6in
[tex]r=\frac{6in}{2}=3in[/tex]Then, the volumen of the given cylinder is: 81pi cubic inches[tex]V=\pi(3in)^2\cdot9in[/tex][tex]V=\pi\cdot9in^2\cdot9in[/tex][tex]V=81\pi in^3[/tex]
