Van Aubel's theorem

Van Aubel's theorem involves starting with a given quadrilateral (a polygon having four sides), construct a square on each side. Then construct the diagonals of each of these squares to locate the center of each square. Van Aubel's theorem holds that the two line segments connecting the centers of opposite squares are of equal length and are at right angles to one another.

ee also

* Petr-Douglas-Neumann theorem
* Thébault's theorem
* Napoleon's theorem

External links

* [http://www.mste.uiuc.edu/dildine/geometry/vanaubel.html Van Aubel's Theorem] : an interactive JavaSketch of the figure.
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* [http://agutie.homestead.com/files/vanaubel.html Proof of Van Aubel by Antonio Gutierrez]
* [http://demonstrations.wolfram.com/VanAubelsTheoremForQuadrilaterals/ Van Aubel's Theorem for Quadrilaterals] and [http://demonstrations.wolfram.com/VanAubelsTheoremForTriangles/ Van Aubel's Theorem for Triangles] by Jay Warendorff, The Wolfram Demonstrations Project.