Brianchon theorem

If an hexagonMathworldPlanetmath ABCDEF (not necessarily convex) is inscribedMathworldPlanetmath into a conic (in particular into a circle), then the three diagonals AD,BE,CF are concurrentMathworldPlanetmath. This theorem is the dual of Pascal lineMathworldPlanetmath theorem. (C. Brianchon, 1806)

Proof:It follows by duality.

Title Brianchon theoremMathworldPlanetmath
Canonical name BrianchonTheorem
Date of creation 2013-03-22 14:04:29
Last modified on 2013-03-22 14:04:29
Owner vmoraru (1243)
Last modified by vmoraru (1243)
Numerical id 7
Author vmoraru (1243)
Entry type Theorem
Classification msc 51-00