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TST Geometry P7

Source: Turkey Team Selection Test 2019 Day 3 Problem 7

March 26, 2019
geometry

Problem Statement

In a triangle ABCABC with ACB=90\angle ACB = 90^{\circ} DD is the foot of the altitude of CC. Let EE and FF be the reflections of DD with respect to ACAC and BCBC. Let O1O_1 and O2O_2 be the circumcenters of ECB\triangle {ECB} and FCA\triangle {FCA}. Show that: 2O1O2=AB2O_1O_2=AB