MathDB

2011 JBMO Shortlist G2

Source: 2011 JBMO Shortlist G2

October 8, 2017

geometryJBMO

Problem Statement

Let

AD,BF

and

{CE}

be the altitudes of

\vartriangle ABC

. A line passing through

{D}

and parallel to

{AB}

intersects the line

{EF}

at the point

{G}

. If

{H}

is the orthocenter of

\vartriangle ABC

, find the angle

{\angle{CGH}}

.

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