The first Yff triangle is the Cevian triangle 
of the first Yff
point. The area of the first Yff triangle is
 |
where 
is the circumradius of the reference
triangle. This is the same area as the second
Yff triangle.
First Yff Triangle
See also
Second Yff Triangle, Yff Central Triangle, Yff Contact Triangle, Yff PointsExplore with Wolfram|Alpha
References
Yff, P. "An Analog of the Brocard Points." Amer. Math. Monthly 70, 495-501, 1963.Referenced on Wolfram|Alpha
First Yff TriangleCite this as:
Weisstein, Eric W. "First Yff Triangle." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/FirstYffTriangle.html