Key Idea: Prism

A prism is a 3D solid formed by extending a 2D shape (the base) straight up or down through a given height.
The name of the prism tells you the shape of its base.

General Rule:

• Base shape determines the type of prism (e.g., triangular prism, rectangular prism).

• Height measures the distance between the two congruent bases.

• Volume and surface area depend on the base’s area and the prism’s height.

Why this matters for the SAT:

Prisms appear in geometry and volume problems. Recognizing that the prism’s name comes from its base shape helps you identify the correct formula and visualize the solid quickly.