Given triangle 
,
there are four lines simultaneously tangent to the 
- and 
-excircles (with centers 
and 
,
respectively). Of these, three correspond to the sidelines of the triangle, and the
fourth is known as the 
-extangent
(Kimberling 1998, p. 162), illustrated above.
The extangents intersect one another pairwise, and their points of intersection form the so-called extangents triangle.
