\input{preamble-standalone.ltx}
\begin{document}

% Ex. No. 92 (Section 11.10.1 : Exemple)

\begin{tikzpicture}[scale=.5]
   \tkzDefPoint(0,0){A}
   \tkzDefPoint(3,-4){B}
   \tkzDefCircle[through](A,B)
   \tkzGetLength{rABpt}
   \tkzpttocm(\rABpt){rABcm}
   \tkzDrawCircle(A,B)
   \tkzDrawPoints(A,B)
   \tkzLabelPoints(A,B)
   \tkzDrawSegment[dashed](A,B)
   \tkzLabelSegment(A,B){%
       $\pgfmathprintnumber{\rABcm}$}
\end{tikzpicture}

\end{document}
