MathDB
2017 IGO Elementary P3

Source: 4th Iranian Geometry Olympiad (Elementary) P3

September 15, 2017
IGOIrangeometry

Problem Statement

In the regular pentagon ABCDEABCDE, the perpendicular at CC to CDCD meets ABAB at FF. Prove that AE+AF=BEAE+AF=BE.
Proposed by Alireza Cheraghi