\input{preamble-standalone.ltx} \begin{document} % Ex. No. 164 (Section 20.2.6 : Calculation of radius example 2) \begin{tikzpicture} \tkzDefPoint(2,2){A} \tkzDefPoint(5,4){B} \tkzDefPoint(4,4){O} \edef\tkzLen{\fpeval{0.0002/0.0001}} \tkzDrawCircle[R](O,\tkzLen cm) \tkzInterLC[R](A,B)(O, \tkzLen cm) \tkzGetPoints{I}{J} \tkzDrawPoints[color=blue](A,B) \tkzDrawPoints[color=red](I,J) \tkzDrawLine(I,J) \end{tikzpicture} \end{document}