Problems(1)
Let H be orthocenter of an acute ΔABC, M is a midpoint of AC. Line MH meets lines AB,BC at points A1,C1 respectively, A2 and C2 are projections of A1,C1 onto line BH respectively. Prove that lines CA2,AC2 meet at circumscribed circle of ΔABC.Proposed by Anton Trygub geometry