arbelos.tex

\documentclass{article}
\usepackage[pdftex,active,tightpage]{preview}
\setlength\PreviewBorder{2mm}
\usepackage{tikz}

\begin{document}
\begin{preview}
\begin{tikzpicture}

    % Draw A
    \coordinate[label=left:$A$]  (A) at (0,0);

    % Draw the Arbelos
    \begin{scope}[shift={(4,0)}, scale=4]
        \draw[fill=green!30, thick](-1,0)
            arc (180:0:1)
            arc (0:180:0.25)
            arc (0:180:0.75);
    \end{scope}

    \begin{scope}[shift={(4,0)}]
        % Draw D
        \coordinate[label=below:$D$] (D) at (2,0);

        % Perpendicular CD
        \draw[thick] (2,0) -- node[] {} (2,3.47);

        % Draw C
        \coordinate[label=above:$C$] (C) at (2,3.47);
    \end{scope}

    % Draw B
    \coordinate[label=below:$B$] (B) at (8,0);

    % Cirlce CD
    \draw[thick] (6,1.735) circle (1.735cm);

    % Bottom line AB
    \draw[thick] (0,0) -- node[] {} (8,0);
  \end{tikzpicture}
\end{preview}
\end{document}