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The Schiffler Point PDF Print E-mail
Written by Andreas Schiffler   
Monday, 18 September 2006
A Schiffler Point? Super!... And keep in mind that any relationships to real-persons are purely coincidental. The Schiffler point is named for Kurt Schiffler (1896-1986), who introduced the point in a problem proposal.

Kurt Schiffler, G. R. Veldkamp, and W. A. van der Spek, Problem 1018 and Solution, Crux Mathematicorum 12 (1986) 176-179.

An accomplished amateur geometer, Schiffler discovered one of the most attractive of the "twentieth-century" triangle centers, now known as the Schiffler point.
schiffler_point.gif

Let I denote the incenter of a triangle ABC. The Schiffler point of ABC is the point of concurrence of the Euler lines of the four triangles BCI, CAI, ABI, ABC. Trilinear coordinates for the Schiffler point are

1/(cos(B) + cos(C)) :
1/(cos(C) + cos(A)) :
1/(cos(A) + cos(B)),

or, equivalently,

(b + c - a)/(b + c) :
(c + a - b)/(c + a) :
(a + b - c)/(a + b),

where a, b, c denote the sidelengths of triangle ABC.

Last Updated ( Monday, 18 September 2006 )
 
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