Problem

Source: 2014 Sharygin Geometry Olympiad Final Round 8.3

Tags: Angle Chasing, geometry



Points $M$ and $N$ are the midpoints of sides $AC$ and $BC$ of a triangle $ABC$. It is known that $\angle MAN = 15^o$ and $\angle BAN = 45^o$. Find the value of angle $\angle ABM$. (A. Blinkov)