Hi Jasmine,

In the glossary section of the Resource room at Math Central there is a definition of a prism.

a geometric solid with two bases that are congruent, parallel polygons and all other faces are parallelograms. It is referred to as a right prism if the faces are rectangles. A prisms is named according to the shape of its bases. e.g. triangular prism

I don't know an easy way to prove this but the volume of a prism is the area of the polygonal base times the height of the prism, where the height of the prism is the perpendicular distance between the parallel, polygonal bases.

Penny