In a triangle ABC with AB<AC<BC, the perpendicular bisectors of AC and BC intersect BC and AC at K and L, respectively. Let O, O1, and O2 be the circumcentres of triangles ABC, CKL, and OAB, respectively. Prove that OCO1O2 is a parallelogram. geometryparallelogrammodular arithmeticcircumcirclepower of a pointradical axisgeometry proposed