The radical circle of the excircles has center at the Spieker center and radius
Its circle function is
corresponding to , the external similitude center of the incircle and circumcircle. No Kimberling centers lie on it.
The radical circle of the excircles has center at the Spieker center and radius
Its circle function is
corresponding to , the external similitude center of the incircle and circumcircle. No Kimberling centers lie on it.
Weisstein, Eric W. "Excircles Radical Circle." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ExcirclesRadicalCircle.html