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. Lester circle theorem follows from a property of rectangular hyperbolas

See also

• Parry circle

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.
• Yiu, Paul (2010), "The circles of Lester, Evans, Parry, and their generalizations" (PDF), Forum Geometricorum, 10: 175–209, MR 2868943.

External links

• The Lester Circle Details of its discovery.
• Lester Circle at MathWorld
• Center of the Dao–Moses circles X(5607) and X(5608)