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Part of 2012 Regional Olympiad of Mexico Center Zone

Problems(1)

Mexico Regional Olympiad. 2012.

Source:

8/1/2013
On an acute triangle ABCABC we draw the internal bisector of <ABC<ABC, BEBE, and the altitude ADAD, (DD on BCBC), show that <CDE<CDE it's bigger than 45 degrees.
trigonometrygeometryincentercircumcircleangle bisectorgeometry unsolved