Let ABC be an acute triangle with circumcenter O and orthocenter H. The circle with center XA passes through the points A and H and is tangent to the circumcircle of the triangle ABC. Similarly, define the points XB and XC. Let OA, OB and OC be the reflections of O with respect to sides BC, CA and AB, respectively. Prove that the lines OAXA, OBXB and OCXC are concurrent. geometryorthocentercircumcircletangent circlesconcurrencyconcurrent