MathDB
Prove ABC is an isosceles triangle

Source: Baltic Way 2008, Problem 20

November 23, 2008
geometryincentergeometry unsolved

Problem Statement

Let M M be a point on BC BC and N N be a point on AB AB such that AM AM and CN CN are angle bisectors of the triangle ABC ABC. Given that \frac {\angle BNM}{\angle MNC} \equal{} \frac {\angle BMN}{\angle NMA}, prove that the triangle ABC ABC is isosceles.
Back to ProblemsView on AoPS