MathDB
Incenter, circumcircle and equal angles

Source: All-Russian MO Round 4, 2005

April 2, 2005
geometryincentercircumcircleangle bisectorsimilar trianglescyclic quadrilateral

Problem Statement

9.4, 10.3 Let II be an incenter of ABCABC (AB<BCAB<BC), MM is a midpoint of ACAC, NN is a midpoint of circumcircle's arc ABCABC. Prove that ∠IMA=∠INB\angle IMA=\angle INB. (A. Badzyan)
Back to ProblemsView on AoPS