how do I find which of the answers in the drop box go with the correct blank?

The first one is a disk, therefore the formula for the volume is:
[tex]V=\pi r^2h[/tex]The second one is a cube, so:
[tex]V=s^3[/tex]The last one is a cone:
[tex]V=\frac{1}{3}\pi r^2h[/tex]