MathDB
Weird geo with two equal circles and centroid

Source: Caucasus MO 2024, Juniors P8

March 15, 2024
geometry

Problem Statement

There are two equal circles of radius 11 placed inside the triangle ABCABC with side BC=6BC = 6. The circles are tangent to each other, one is inscribed in angle BB, the other one is inscribed in angle CC. (a) Prove that the centroid MM of the triangle ABCABC does not lie inside any of the given circles. (b) Prove that if MM lies on one of the circles, then the triangle ABCABC is isosceles.