: Intersecting, parallel, and skew lines; parallelism of lines and planes; parallel planes.

This foundational section covers geometric figures on a flat surface.

This stage focuses on properties of figures in three-dimensional space. The content is typically divided as follows:

: Basic axioms and theorems regarding points, lines, and planes in space.

: Advanced properties, including inscribed and circumscribed polyhedra.

: Perpendicular lines and planes; theorems on three perpendiculars; distances and angles in space.

: Method of coordinates in space and scalar product of vectors.