Excentral Triangle
The Triangle 
with Vertices corresponding to the Excenters of a givenTriangle 
, also called the Tritangent Triangle.
Beginning with an arbitrary Triangle , find the excentral triangle 
. Then find the excentral triangle 
of thatTriangle, and so on. Then the resulting Triangle 
approaches an Equilateral Triangle.
Call 
the Triangle tangent externally to the Excircles of . Then the Incenter 
of 
coincides with the Circumcenter 
of Triangle 
, where 
are theExcenters of . The Inradius 
of the Incircle of is
where
is the Circumradius of , 
is the Inradius, and 
are the Exradii(Johnson 1929, p. 192).See also Excenter, Excenter-Excenter Circle, Excircle, Mittenpunkt
References
Johnson, R. A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Boston, MA: Houghton Mifflin, 1929.
- Cushion
- Cusp
- Cusp Catastrophe
- Cusp Form
- Cusp Map
- Cusp Point
- Cutting
- Cut-Vertex
- CW-Approximation Theorem
- CW-Complex
- Transfinite Diameter
- Transfinite Number
- Transform
- Transformation
- Transitive
- Transitive Closure
- Transitive Reduction
- Transitivity Class
- Translation
- Translation Relation
- Transpose
- Transpose Map
- Transposition
- Transposition Group
- Transposition Order