BC bisector of <DBE wanted, AB=AC, AC = 2AD and AE = 2AC
Source: 2014 All-Ukrainian Correspondence MO of magazine ''In the World of Mathematics'', grades 5-12 p7
April 27, 2021
geometryisoscelesangle bisectorUkraine Correspondence
Problem Statement
Let be an isosceles triangle (). The points and were marked on the ray so that and . Prove that is the bisector of the angle .