Constructions (accurate drawings) can be made using a ruler, a pair of compasses and a pencil. A line which cuts an angle into two equal side angles is called an angle bisector. In geometry a ...

The six intersection points of a triangle’s non-parallel altitudes and perpendicular bisectors are the vertices of two congruent minor periambic triangles which are inversely similar to the original.

Summary We prove the next generalization of the Steiner-Lehmus theorem: if two equal cevians intersect with each other on the angle bisector of the third triangle vertex, then the triangle is ...