Can someone please help me find the volume for this? I've tried for 45 minutes and can't get it.

The triangular face consists of a right triangle, so the prism itself is half of a 10x3x4 box. Such a box would have a volume of (10 ft)•(3 ft)•(4 ft) = 120 ft³. So the prism has a volume of 60 ft³.