A pyramid is a solid figure with a polygonal base and triangular faces that meet at a single point called an apex. It has a base, lateral faces that are triangles, lateral edges, and an altitude. The characteristics are that the lateral edges are congruent, lateral faces are congruent isosceles triangles, and the altitude meets the base at its center. Pyramids can be classified by their base as right, triangular, pentagonal, or hexagonal pyramids.