MathDB

easy angle chasing for 8graders

Source: 2015 Sharygin Geometry Olympiad Correspondence Round P2

August 2, 2018

geometryCircumcenterorthocenterincenterangles

Problem Statement

Let

O

and

H

be the circumcenter and the orthocenter of a triangle

ABC

. The line passing through the midpoint of

OH

and parallel to

BC

meets

AB

and

AC

at points

D

and

E

. It is known that

O

is the incenter of triangle

ADE

. Find the angles of

ABC