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

% Ex. No. 85 (Section 12.2.2 : Example of tangents passing through an external point )

\begin{tikzpicture}[scale=.8]
  \tkzDefPoint(3,3){c}
  \tkzDefPoint(6,3){a0}
  \tkzRadius=1 cm
  \tkzDrawCircle[R](c,\tkzRadius)
  \foreach \an in {0,10,...,350}{
     \tkzDefPointBy[rotation=center c angle \an](a0)
     \tkzGetPoint{a}
     \tkzDefTangent[from with R = a](c,\tkzRadius)
     \tkzGetPoints{e}{f}
     \tkzDrawLines[color=magenta](a,f a,e)
      \tkzDrawSegments(c,e c,f)
      }%
\end{tikzpicture}

\end{document}