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arXiv · 1004.2829

An euclidean affine invariant of quadrilaterals

Helmut Kahl
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Abstract

A certain real number, depending on two neighbouring sides of a quadrilateral and the diagonal meeting these two sides at their common point, is shown to be invariant under affinity. As an application we demonstrate a nice formula for the area of a finite sector at centre of a planar quadric with point symmetry.

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Helmut Kahl. 2010-04-16. An euclidean affine invariant of quadrilaterals. https://arxiv.org/abs/1004.2829

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