Line Segments through the Vertices and the Circumcenter of an Acute Triangle
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Let ABC be an acute triangle, O its circumcenter, and R its circumradius. Let D, E, and F be the points along AO, BO, and CO across from A, B, and C. Then .
Contributed by: Jay Warendorff (March 2011)
Open content licensed under CC BY-NC-SA
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See the First Iberoamerican Olympiad (problem 6).