The lateral faces of a prism - pentagonal or other - are rectangular.
4 lateral faces
They are the lateral faces.
The lateral face for a prism or pyramid is any edge or face which is not part of a base.
Lateral Face - In a prism, the faces that are not bases. In a pyramid, faces that intersect at the vertex.
Length of prism * perimeter of triangular face.
A prism has a variety of bases but the sides are always parallelograms. A triangular prism has a triangle as the two bases and parallelograms as lateral sides. A pyramid has a variety of bases but the sides are triangles.