If a plane intersects all edges of a cone parallel to its bases, it divides the solid into two others: a new cone and a cone trunk. As the trunk of the regular circular cone follows, we have:
- the major and minor bases are parallel;
- The height of the trunk is given by the distance between the planes that contains the bases.
a) lateral area
b) total area
Where V is the volume of the cone and V 'is the volume of the cone obtained by the section, the relations shall be