Given a line having trilinear coordinate equation
with respect to a reference triangle , the point
is called the trilinear pole of the line with respect to (Kimberling 1998, p. 38).
The following table gives the trilinear poles for some named lines.
line | trilinear pole | Kimberling center | |
antiorthic axis | incenter | ||
Brocard axis | focus of the Kiepert parabola | ||
de Longchamps line | third
Brocard point | ||
Euler line | |||
Fermat axis | Tixier point | ||
Gergonne line | Gergonne
point | ||
Lemoine axis | symmedian
point | ||
line at infinity | triangle centroid | ||
Nagel line | Yff parabolic point | ||
orthic axis | orthocenter | ||
Soddy line | |||
van Aubel line |
Let
be the intercept of the line
and
, and let
be the harmonic conjugate
of
with respect to
and
.
Similarly define
and
.
Then
is the Cevian triangle of the trilinear pole of
.