Prism 1) 4×5×3 = 60
Prism 2) 5×5×10 = 250
Prism 3) I can't see the numbers but I'm guessing the answer would be 546, as it's the only one left.
Prism 4) 5×3×3 = 45
Prism 5) 6×6×6 = 216
Hope this helps, although, if you don't understand something, ask me!