and CF are concurrent at the Yff center of congruence. This fact gives a geometrical construction for locating the Yff center of congruence. A computer assisted search of the properties of the Yff central triangle has generated several interesting results relating to properties of the Yff central triangle. Generalization The geometrical construction for locating the Yff center of congruence has an interesting generalization. The generalisation begins with an arbitrary point P in the plane of a triangle ABC. Then points D, E, F are taken on the sides BC, CA, AB such that ∠BPD = ∠DPC, ∠CPE = ∠EPA, and ∠APF = ∠FPB. The generalization asserts that the lines AD, BE, CF'' are concurrent. See also Congruent isoscelizers point Central triangle References Triangle centers