The simple closed curve is called the base of the cone, and the fixed noncoplanar point is the vertex. ... Figure %: A right circular cone It is easy to see the close relationship between pyramids and cones. The only difference is the base--a pyramid is a cone with a polygonal base.
The pyramid and cones are alike because their lateral faces meet at a vertex. Also, a pyramid becomes a cone as the number of sides of its base becomes larger and larger.
