The théorème de Thalès proportions triangles and its reciprocal are fundamental geometric principles dealing with parallel lines and proportional segments in triangles.
- The theorem states that when two lines intersect two other lines, corresponding segments are proportional
- The reciprocal theorem provides conditions for determining when lines are parallel based on proportional segments
- Both theorems are essential tools in geometry for proving similarity of triangles and working with parallel lines
- Applications include practical measurements and geometric constructions
- Understanding these theorems helps in solving complex geometric problems involving droites parallèles triangles proportionnels
