Let ,
,
and
be the vertices of the inner Soddy triangle, and
also let ,
,
and
be the pairwise contact points of the three tangent circles. Then the lines , , and concur at a point known as the second Eppstein point
(Kimberling), denoted by Eppstein (2001). Although Eppstein (2001) actually cited
(Oldknow 1996), he missed the fact that is equivalent to the outer Oldknow point defined by Oldknow
(1996).
Danneels, E. "The Eppstein Centers and the Kenmotu Points." Forum Geom.5, 173-180, 2005. http://forumgeom.fau.edu/FG2005volume5/FG200523index.html.Eppstein,
D. "Tangent Spheres and Triangle Centers." Amer. Math. Monthly108,
63-66, 2001.Kimberling, C. "Encyclopedia of Triangle Centers: X(482)=2nd
Eppstein Point." http://faculty.evansville.edu/ck6/encyclopedia/ETC.html#X482.Oldknow,
A. "The Euler-Gergonne-Soddy Triangle of a Triangle." Amer. Math. Monthly103,
319-329, 1996.
,
,
and 
be the vertices of the inner Soddy triangle, and
also let 
,
,
and 
be the pairwise contact points of the three tangent circles. Then the lines 
, 
, and 
concur at a point known as the second Eppstein point
(Kimberling), denoted 
by Eppstein (2001). Although Eppstein (2001) actually cited
(Oldknow 1996), he missed the fact that 
is equivalent to the outer Oldknow point defined by Oldknow
(1996).
and the tangential
triangles of its inner Soddy Triangle (Oldknow
1996).
is the area of 
,
and is Kimberling center 
.
