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In a triangle abc...

Source: Swiss Imo Selection 2006

May 25, 2006
geometrytrigonometrytrig identitiesLaw of Sinesgeometry proposed

Problem Statement

In the triangle A,B,CA,B,C, let DD be the middle of BCBC and EE the projection of CC on ADAD. Suppose ∠ACE=∠ABC\angle ACE = \angle ABC. Show that the triangle ABCABC is isosceles or rectangle.
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