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

% Ex. No. 142 (Section 18.1.3 : Circles inscribed and circumscribed for a given triangle)

\begin{tikzpicture}[scale=1]
   \tkzDefPoint(2,2){A}
   \tkzDefPoint(5,-2){B}
   \tkzDefPoint(1,-2){C}
   \tkzDefCircle[in](A,B,C)
   \tkzGetPoint{I}    \tkzGetLength{rIN}
   \tkzDefCircle[circum](A,B,C)
   \tkzGetPoint{K}   \tkzGetLength{rCI}
   \tkzDrawPoints(A,B,C,I,K)
   \tkzDrawCircle[R,blue](I,\rIN pt)
   \tkzDrawCircle[R,red](K,\rCI pt)
   \tkzLabelPoints[below](B,C)
   \tkzLabelPoints[above left](A,I,K)
   \tkzDrawPolygon(A,B,C)
\end{tikzpicture}

\end{document}