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Heptagon Theorem


HeptagonTheorem

Let H be a heptagon with seven vertices given in cyclic order inscribed in a conic. Then the Pascal lines of the seven hexagons obtained by omitting each vertex of H in turn and keeping the remaining vertices in the same cyclic order are the sides of a heptagon I which circumscribes a conic.

Moreover, the Brianchon points of the seven hexagons obtained by omitting the sides of I one at a time and keeping the remaining sides in the natural cyclic order are the vertices of the original heptagon.


See also

Brianchon Point, Conic Section, Heptagon, Hexagon, Pascal Lines

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References

Evelyn, C. J. A.; Money-Coutts, G. B.; and Tyrrell, J. A. "The Heptagon Theorem." §2.1 in The Seven Circles Theorem and Other New Theorems. London: Stacey International, pp. 8-11, 1974.

Referenced on Wolfram|Alpha

Heptagon Theorem

Cite this as:

Weisstein, Eric W. "Heptagon Theorem." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/HeptagonTheorem.html

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