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.
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.
Weisstein, Eric W. "First Yff Triangle." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/FirstYffTriangle.html