Tangential triangle
That is, the lines connecting the vertices of the tangential triangle and the corresponding vertices of the reference triangle are concurrent.[1]: p.
165 The center of perspectivity, where these three lines meet, is the symmedian point of the triangle.
Any two of these are concurrent with the third symmedian of the reference triangle.[3]: p.
214 The reference triangle's circumcircle, its nine-point circle, its polar circle, and the circumcircle of the tangential triangle are coaxal.[1]: p.
This elementary geometry-related article is a stub.
Reference triangle
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ABC
Circumcircle of
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ABC
Orthic triangle
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GHI
of
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ABC
Tangential triangle
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DEF
of
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ABC