Cone

From Conservapedia

In mathematics, a right circular cone is a three dimensional object formed by rotating two intersecting lines about the line which bisects the angle between them.

The intersection of a plane with this object forms an important set of two dimensional functions, called the conic sections.

Cones in general do not have to be "right" or "circular", and may be truncated, i.e., not extend to infinity. A familiar example of a (doubly) truncated cone is a basketball net.

The volume of a cone is equal to the product of the base, height, and one third.