The quadratrix was discovered by Hippias of Elias in 430 BC, and later studied by Dinostratus in 350
BC (MacTutor Archive). It can be used for Angle Trisection or, more generally, division of an
Angle into any integral number of equal parts, and Circle Squaring. In Polar Coordinates,

so

which is proportional to the Cochleoid.

**References**

Lawrence, J. D. *A Catalog of Special Plane Curves.* New York: Dover, pp. 195 and 198, 1972.

Lee, X. ``Quadratrix of Hippias.'' http://www.best.com/~xah/SpecialPlaneCurves_dir/QuadratrixOfHippias_dir/quadratrixOfHippias.html

MacTutor History of Mathematics Archive. ``Quadratrix of Hippias.'' http://www-groups.dcs.st-and.ac.uk/~history/Curves/Quadratrix.html.

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1999-05-25