MathDB
Cono Sur Olympiad 2012

Source: Problem 6

November 3, 2012
geometrycircumcirclegeometric transformationreflectionquadraticsgeometry proposed

Problem Statement

6. Consider a triangle ABCABC with 1<ABAC<321 < \frac{AB}{AC} < \frac{3}{2}. Let MM and NN, respectively, be variable points of the sides ABAB and ACAC, different from AA, such that MBACNCAB=1\frac{MB}{AC} - \frac{NC}{AB} = 1. Show that circumcircle of triangle AMNAMN pass through a fixed point different from AA.