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geometry

Source:

January 29, 2016
geometrycircumcircleperpendicular bisector

Problem Statement

Let ABCABC be an acute-angled triangle with HH orthocenter, OO circumcenter. [AH][AH]'s perpendicular bisector intersects with [AB][AB] and [AC][AC] at DD and EE respectively. Prove that ∠ADE=∠BDO\angle ADE =\angle BDO
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