Outer Pentagon Point


Let A^' be the outermost vertex of the regular pentagon erected outward on side BC of a reference triangle DeltaABC. Similarly, define B^' and C^'. The triangle DeltaA^'B^'C^' is then perspective to DeltaABC, and the perspector is known as the outward pentagon point. It is Kimberling center X_(1139) and has equivalent triangle center functions


where Delta is the area of the reference triangle.

See also

Inner Pentagon Point

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Kimberling, C. "Encyclopedia of Triangle Centers: X(1139)=Outer Pentagon Point."

Referenced on Wolfram|Alpha

Outer Pentagon Point

Cite this as:

Weisstein, Eric W. "Outer Pentagon Point." From MathWorld--A Wolfram Web Resource.

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