Source: wikibot/descartes-theorem
= Descartes' theorem
{wiki=Descartes'_theorem}
Descartes' theorem, also known as the "kissing circles theorem," relates to the geometric properties of circles. Specifically, it provides a relationship between the curvatures (or bending) of four mutually tangent circles. In this context, the curvature of a circle is defined as the reciprocal of its radius (i.e., \\( k = \\frac\{1\}\{r\} \\)).