The resultant of the vectors represented by the three Radii from the center of a Triangle's Circumcircle to its Vertices is the segment extending from the Circumcenter to the Orthocenter.
See also Circumcenter, Circumcircle, Orthocenter, Triangle
References
Dörrie, H. 100 Great Problems of Elementary Mathematics: Their History and Solutions. New York: Dover, p. 142, 1965.