% Exercise 6.3, second part
\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}
\begin{tikzpicture}[x=1cm,y=1cm]
  % draw the outer circle
  \draw (0,0) circle (2);
  % draw the inner circles
  % loops: see circles_exercise.tex

  % polar coordinates might be helpful: (30:1) means 'angle = 30 degrees' and 'radius = 1'
  \draw (42:1) circle (1);

  % todo: complete this example!

  % for the bonus problem:
  % filling circles with blue: use \fill[blue] instead of \draw
  % change opacity of fill colour: use \fill[blue, opacity=0.5] instead, etc.
\end{tikzpicture}
\end{document}
