The volume of a sphere is: $\displaystyle{V}=\frac{{4}}{{3}}\pi{{r}}^{{3}}\usepackage{cmbright}\Huge\$

The radius of the sphere is half the diameter, or $\displaystyle\frac{{12}}{{2}}={6}\usepackage{cmbright}\Huge\$ centimeters. Substitute $\displaystyle{r}={6}\usepackage{cmbright}\Huge\$ into the formula:

$\displaystyle{V}=\frac{{4}}{{3}}\pi{{\left({6}\right)}}^{{3}}\usepackage{cmbright}\Huge\$

$\displaystyle{V}=\frac{{4}}{{3}}\pi{\left({216}\right)}\usepackage{cmbright}\Huge\$

$\displaystyle{V}={288}\pi\usepackage{cmbright}\Huge\$ cubic centimeters