Problem

Source: Tuymaada 2014, Day 2, Problem 2, Junior League

Tags: trigonometry, geometry unsolved, geometry, Tuymaada



Radius of the circle $\omega_A$ with centre at vertex $A$ of a triangle $\triangle{ABC}$ is equal to the radius of the excircle tangent to $BC$. The circles $\omega_B$ and $\omega_C$ are defined similarly. Prove that if two of these circles are tangent then every two of them are tangent to each other. (L. Emelyanov)