Kegel; kegelförmig verjüngtes Maschinenelement.
In geometry, a solid or surface consisting of the set of all straight lines passing through a fixed point (the vertex) and the points of a circle or ellipse whose plane does not contain the vertex. A circular cone of perpendicular height, with its apex above the center of the circle, is known as a right circular cone; it is generated by rotating an isosceles triangle or framework about its line of symmetry. A right circular cone of perpendicular height h and base of radius r has a volume V = 1/3pr2h. The distance from the edge of the base of a cone to the vertex is called the slant height. In a right circular cone of slant height l, the curved surface area is prl, and the area of the base is pr2. Therefore the total surface area A = prl + pr2 = pr(l + r).