Prisms: Figures 1-4

Prisms are commonly used to bend the path of light in devices such as binoculars and periscopes. White light passed through a glass prism will divide into the colors of the spectrum. In geometry, prisms are three-dimensional solids in which the bases are two parallel planes, and the faces in these planes are congruent polygons. As shown in figure 1, the lateral faces of the prism are parallelograms. Figure 2 depicts a prism in which all six bases are rectangular parallelograms, a special case of a prism called a rectangular parallelopiped. Figure 3 is also a parallelopiped, but each of the faces is a square, forming a cubic solid. A truncated prism, shown in figure 4, is a portion of a prism formed by cutting all lateral edges with a plane not parallel to the base.