Prisms are solids (three‐dimensional figures) that, unlike planar figures, occupy space. They come in many shapes and sizes. Every prism has the following characteristics:

**Bases:**A prism has two bases, which are congruent polygons lying in parallel planes.

**Lateral edges:**The lines formed by connecting the corresponding vertices, which form a sequence of parallel segments.

**Lateral faces:**The parallelograms formed by the lateral edges.

A prism is named by the polygon that forms its base, as follows:

**Altitude:**A segment perpendicular to the planes of the bases with an endpoint in each plane.

**Oblique prism:**A prism whose lateral edges are not perpendicular to the base.

**Right prism:**A prism whose lateral edges are perpendicular to the bases. In a right prism, a lateral edge is also an altitude.

In Figure 1*h*.

**Figure 1 **Different types of prisms.