Solid geometry is that subsection of geometry that deals with figures in three-dimensional space. Euclidean geometry, sometimes called parabolic geometry, is divided into two subsections: plane geometry, geometry dealing with figures in a plane, and solid geometry, geometry dealing with solids in three-dimensional space. Solid geometry is sometimes called three-dimensional Euclidean geometry and deals with solids, such as polyhedra and spheres, and lines and planes in three-dimensional space. Solid geometry is concerned with the study of figures in three-dimensional Euclidean space, which is usually denoted R³.

Solid geometry is a branch of Euclidean geometry, developed by Greek mathematician Euclid in the 4th century B.C., that is governed by Euclid's five postulates as laid out in his work The Elements. More specifically the basics of solid geometry are described in Book XI of The Elements. Book XI consists of 28 definitions, in which Euclid departed from traditional...