MathDB

Fifth problem

Source: Cono sur 2018

August 27, 2018

geometryincentercircumcirclecono sur

Problem Statement

Let

O

be an acute-angled triangle with

\angle BAC = 60^{\circ}

and with incenter

I

and circumcenter

O

. Let

H

be the point diametrically opposite(antipode) to

O

in the circumcircle of

\triangle BOC

. Prove that

IH=BI+IC

.

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