# Designation of points and lines

**Point and line are the main geometric figures.**

Points are designated by uppercase Latin letters: А, В, С, …

Lines are designated by lowercase Latin letters *a, b, c* …

If point A lies on line *a**, * then it is written as А ∈ *a* (the sign ∈ designates belonging),

If point A does not lie on line *a*, then it is written as А ∉ *a.*