Yff Center of Congruence

Let three Isoscelizers, one for each side, be constructed on a Triangle such that the four interior triangles they determine are congruent. Now parallel-displace these Isoscelizers until they concur in a single point. This point is called the Yff center of congruence and has Triangle Center Function

$$\alpha=\sec({\textstyle{1\over 2}}A).$$

See also Congruent Isoscelizers Point, Isoscelizer

References

Kimberling, C. ``Yff Center of Congruence.'' http://cedar.evansville.edu/~ck6/tcenters/recent/yffcc.html.