The tip here is to compute per solid. First the cylinder then the half sphere.
To get the volume of the cylinder we have:
V=πr^2h where the r is 3 and h is 12. So the result is 339.29.
The volume of the sphere is V =(4/3)*π*r^3 where the r is still 3. The answer then is 113.1.
The answer is then 144pi
