The Radical Lines of three Circles are Concurrent in a point known as the radical center (also called the Power Center). This theorem was originally demonstrated by Monge (Dörrie 1965, p. 153).
See also Apollonius' Problem, Concurrent, Monge's Problem, Radical Line
References
Dörrie, H. 100 Great Problems of Elementary Mathematics: Their History and Solutions. New York: Dover, 1965.
Johnson, R. A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Boston, MA:
Houghton Mifflin, p. 32, 1929.