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

% Ex. No. 39 (Section  8.2 : Point on a circle)

\begin{tikzpicture}
  \tkzDefPoints{0/0/A,4/0/B,0.8/3/C}
  \tkzDefPointOnCircle[angle=90,center=B,
      radius=1 cm]
  \tkzGetPoint{I}
  \tkzDrawCircle[R,teal](B,1cm)
   \tkzDrawPoint[teal](I)
  \tkzDefCircle[circum](A,B,C)
  \tkzGetPoint{G} \tkzGetLength{rG}
  \tkzDefPointOnCircle[angle=30,center=G,
  radius=\rG pt]
 \tkzGetPoint{J}
  \tkzDrawPoints(A,B,C)
  \tkzDrawCircle(G,J)
  \tkzDrawPoint(G)
  \tkzDrawPoint[red](J)
\end{tikzpicture}

\end{document}
