line JK of intersection points of 2 lines passes through the midpoint of BC
Source: Rioplatense Olympiad 2018 level 3 p4
December 11, 2018
geometrymidpointintersectionscircumcirclearc midpoint
Problem Statement
Let be an acute triangle with . be the circumcircle circumscribed to the triangle and the midpoint of the smallest arc of this circle. Let and points of the segments and respectively such that . Let be the second intersection point of the circumcircle circumscribed to with . Let and be the intersections of lines and with other than , respectively. Let and be the intersection points of lines and with lines and respectively. Show that the line passes through the midpoint of