MathDB

SKMO 2023 P3

Source:

April 4, 2023

geometry

Problem Statement

In acute triangle

ABC

let

H

be its orthocenter and

I

be its incenter. Let

D

be the projection of point

I

onto the line

BC

and

E

be the reflection of point

A

in point

I

. Further, let

F

be the projection of point

H

onto the line

ED

. Prove that points

B, H, F

and

C

lie on circle.

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