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

% Ex. No. 117 (Section 16.0.2 : Option \tkzname{in} or \tkzname{incentral} )

\begin{tikzpicture}[scale=1]
  \tkzDefPoints{ 0/0/A,5/0/B,1/3/C}
  \tkzDefSpcTriangle[in,name=I](A,B,C){_a,_b,_c}
  \tkzInCenter(A,B,C)\tkzGetPoint{I}
  \tkzDrawPolygon[red](A,B,C)
  \tkzDrawPolygon[blue](I_a,I_b,I_c)
  \tkzDrawPoints(A,B,C,I,I_a,I_b,I_c)
  \tkzDrawCircle[in](A,B,C)
  \tkzDrawSegments[dashed](A,I_a B,I_b C,I_c)
 \tkzAutoLabelPoints[center=I,
  blue,font=\scriptsize](I_a,I_b,I_c)
 \tkzAutoLabelPoints[center=I,red,
  font=\scriptsize](A,B,C,I_a,I_b,I_c)
\end{tikzpicture}

\end{document}