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starting with 3 right triangles, find area of a quadrilateral

Source: Mexican Mathematical Olympiad 1993 OMM P1

July 29, 2018
geometryarea of a triangleright triangles

Problem Statement

ABCABC is a triangle with A=90o\angle A = 90^o. Take EE such that the triangle AECAEC is outside ABCABC and AE=CEAE = CE and AEC=90o\angle AEC = 90^o. Similarly, take DD so that ADBADB is outside ABCABC and similar to AECAEC. OO is the midpoint of BCBC. Let the lines ODOD and ECEC meet at DD', and the lines OEOE and BDBD meet at EE'. Find area DEDEDED'E' in terms of the sides of ABCABC.