Let ABC an isosceles triangle and BC>AB=AC. D,M are respectively midpoints of BC,AB. X is a point such that BX⊥AC and XD∣∣AB. BX and AD meet at H. If P is intersection point of DX and circumcircle of AHX (other than X), prove that tangent from A to circumcircle of triangle AMP is parallel to BC. geometrycircumcircletrapezoidgeometry proposed