MathDB
Romania NMO 2023 Grade 6 P4

Source: Romania National Olympiad 2023

April 14, 2023
geometryangles

Problem Statement

Let ABCABC be a triangle with BAC=90\angle BAC = 90^{\circ} and ACB=54.\angle ACB = 54^{\circ}. We construct bisector BD(DAC)BD (D \in AC) of angle ABCABC and consider point E(BD)E \in (BD) such that DE=DC.DE = DC. Show that BE=2AD.BE = 2 \cdot AD.