Yff triangles

The Yff contact triangle Δ X_A X_B X_C (a term coined here for the first time), is the Cevian triangle of Kimberling center X_190. It is the polar triangle of the Yff parabola. It has the trilinear vertex matrix [0 | (a c)/(c - a) | (a b)/(b - a) (b c)/(b - c) | 0 | (a b)/(a - b) (b c)/(b - c) | (a c)/(c - a) | 0]. The vertices are the points of contact of the Yff parabola with the sidelines of the reference triangle.

first Yff triangle | Yff contact circle