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

% Ex. No. 33 (Section  6.1.8 : Using option \IoptName{tkzDefTriangleCenter}{nagel})

  \begin{tikzpicture}[scale=.5]
  \tkzDefPoints{0/0/A,6/0/B,4/6/C}
  \tkzDefSpcTriangle[ex](A,B,C){Ja,Jb,Jc}
  \tkzDefSpcTriangle[extouch](A,B,C){Ta,Tb,Tc}
  \tkzDrawPoints(Ja,Jb,Jc,Ta,Tb,Tc)
  \tkzLabelPoints(Ja,Jb,Jc,Ta,Tb,Tc)
  \tkzDrawPolygon[blue](A,B,C)
  \tkzDefTriangleCenter[nagel](A,B,C) \tkzGetPoint{Na}
  \tkzDrawPoints[blue](B,C,A)
  \tkzDrawPoints[red](Na)
  \tkzLabelPoints[blue](B,C,A)
  \tkzLabelPoints[red](Na)
  \tkzDrawLines[add=0 and 1](A,Ta B,Tb C,Tc)
  \tkzShowBB\tkzClipBB
  \tkzDrawLines[add=1 and 1,dashed](A,B B,C C,A)
  \tkzDrawCircles[ex,gray](A,B,C C,A,B B,C,A)
  \tkzDrawSegments[dashed](Ja,Ta Jb,Tb Jc,Tc)
  \tkzMarkRightAngles[fill=gray!20](Ja,Ta,C Jb,Tb,A Jc,Tc,B)
\end{tikzpicture}

\end{document}
