please explain how to do!

Answer: [tex]V=108in^3[/tex]
Step-by-step explanation:
To find the volume od the object you must add the volume of the cylinder and the volume of the cone, as following:
[tex]V=V_{cylinder}+V{cone}\\\\V=(\pi\ *r^2*h_{cylinder})+(\frac{\pi\ *r^2*h_{cone}}{3})[/tex]
Where is the the radius, which is:
[tex]r=\frac{4in}{2}=2in[/tex]
Substituting values, you obtain:
[tex]V=(3*(2in)^2*(8in))+(\frac{3*(2)^2*(3in)}{3})[/tex]
[tex]V=108in^3[/tex]