Cones Cones are three-dimensional closed surfaces.In general use, the term cone refers to a right circular cone with its end closed to form a circular base surface. The vertex of the cone (the point) is not in the same plane as the base. Cones are not called polyhedra since their faces are not polygons. In many ways, however, a cone is similar to a pyramid. A cone's base … [Read more...] about Cones