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BD+BE=2CH

Source: Saint Petersburg olympiad 2024, 9.5

September 22, 2024
geometry

Problem Statement

Let AHAH be altitude in acute trinagle ABCABC, inscribed in circle ss. Points DD and EE are chosen on segment BHBH. Points XX and YY are chosen on rays ADAD and AEAE, respectively, such that midpoints of segments DXDX and EYEY lies on ss. Suppose that points BB, XX, YY and CC are concyclic. Prove that BD+BE=2CHBD+BE=2CH.