MathDB
tangent (ACE) and (BDM), <B = 3<C

Source: 2023 IGO Intermediate P3

January 18, 2024
geometrytangent circles

Problem Statement

Let ω\omega be the circumcircle of the triangle ABCABC with B=3C\angle B = 3\angle C. The internal angle bisector of A\angle A, intersects ω\omega and BCBC at MM and DD, respectively. Point EE lies on the extension of the line MCMC from MM such that MEME is equal to the radius of ω\omega. Prove that circumcircles of triangles ACEACE and BDMBDM are tangent.
Proposed by Mehran Talaei - Iran