The formula for the volume of a sphere is
[tex]V=\frac{4\pi}{3}r^3[/tex]where r represents the radius of the sphere.
A hemisphere is half of a sphere, therefore, it has half the volume of a sphere. A formula for the volume of a hemisphere is half the volume of a sphere, which is
[tex]\frac{V}{2}=\frac{1}{2}\times\frac{4}{3}\pi r^3=\frac{2}{3}\pi r^3[/tex]The volume of a hemisphere is
[tex]V=\frac{2}{3}\pi r^3[/tex]