MathDB
RMO KV 2024 Q5

Source: RMO KV 2024 Q5

November 3, 2024
geometry

Problem Statement

Let ABCABC be a triangle with ABC=20\angle ABC = 20^{\circ} and ACB=40\angle ACB = 40^{\circ}. Let DD be a point on BCBC such that BAD=DAC\angle BAD = \angle DAC. Let the incircle of triangle ABCABC touch BCBC at EE. Prove that BD=2CEBD = 2 \cdot CE.