MathDB
Show that angle BMN=90

Source: Moldova TST 2020

March 7, 2020
geometry

Problem Statement

Let ΔABC\Delta ABC be an acute triangle and Ω\Omega its circumscribed circle, with diameter APAP. Points EE and FF are the orthogonal projections from BB on ACAC and APAP, points MM and NN are the midpoints of segments EFEF and CPCP. Prove that BMN=90\angle BMN=90.