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Prove that the angle AED is not acute

Source: Tournament of Towns Spring 2003 - Junior A-Level - Problem 6

June 14, 2011
geometrytrapezoidinequalitiesgeometric transformationreflectiontriangle inequalitygeometry unsolved

Problem Statement

A trapezoid with bases ADAD and BCBC is circumscribed about a circle, EE is the intersection point of the diagonals. Prove that AED\angle AED is not acute.