Lester's theorem

Lester's theorem

In Euclidean plane geometry, Lester's theorem, named after June Lester, states that in any scalene triangle, the two Fermat points, the nine-point center, and the circumcenter are concyclic.

References

* Clark Kimberling, "Lester Circle", "Mathematics Teacher", volume 89, number 26, 1996.
* June A. Lester, "Triangles III: Complex triangle functions", "Aequationes Mathematicae", volume 53, pages 4–35, 1997.
* Michael Trott, "Applying GroebnerBasis to Three Problems in Geometry", "Mathematica in Education and Research", volume 6, pages 15–28, 1997.
* Ron Shail, "A proof of Lester's Theorem", "Mathematical Gazette", volume 85, pages 225–232, 2001.
* John Rigby, "A simple proof of Lester's theorem", "Mathematical Gazette", volume 87, pages 444–452, 2003.
* J.A. Scott, "On the Lester circle and the Archimedean triangle", "Mathematical Gazette", volume 89, pages 498–500, 2005.
* Michael Duff, "A short projective proof of Lester's theorem", "Mathematical Gazette", volume 89, pages 505–506, 2005.
* Stan Dolan, "Man versus Computer", "Mathematical Gazette", volume 91, pages 469–480, 2007.

External links

* [http://thejuniverse.org/PUBLIC/LesterCircle/index.html The Lester Circle] Details of its discovery.
* [http://mathworld.wolfram.com/LesterCircle.html Lester Circle] at MathWorld


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