Exercices de Géométrie plane

This document is a set of theoretical notes and applications in plane geometry and analytic geometry intended for students preparing the entrance examination for civil engineering studies at the University of Liège. It reviews key geometric notions such as circles, tangents, chords, and various types of angles (opposite, corresponding, alternate interior/exterior, parallel- and perpendicular-sided angles), as well as central, inscribed, and tangential angles in a circle. The text also introduces and classifies polygons, with particular attention to regular polygons and their symmetry properties. The emphasis is on understanding fundamental concepts and knowing the statements of main theorems and results rather than memorizing the notes verbatim; detailed proofs are omitted and referred back to secondary-school courses. The document also includes sections with worked exercises that illustrate different methods for applying the theoretical concepts, all of which are acceptable at the entrance exam if properly justified.