4_7

\documentclass{standalone}
\usepackage[T1]{fontenc}
\usepackage[latin2]{inputenc}
\usepackage[english]{babel}
\usepackage{tikz}
\usetikzlibrary{calc,through,backgrounds,positioning,fit}
\usetikzlibrary{shapes,arrows,shadows}



\begin{document}

    \begin{tikzpicture}[scale=1,inner sep=0.4mm]
    \coordinate (O) at (0,0);
    \coordinate (A) at (-75:2cm);
    \coordinate (B) at (85:2cm);
    \draw (0,0) circle (57pt);
    \node at (O) [circle,fill=black!80!white] {};
    \fill[draw=black, fill=green]
    (O) -- (A) arc(-75:85:2cm) --cycle;
    \node at (O) [left=2pt] {$O$};
    \node at(0.8,0) {$\alpha = 160$};
    \node at (0.31,-1.75){$A$};
    \node at (0,1.80){$B$};
    \node at (A) [circle,fill=black!80!white] {};
    \node at (B) [circle,fill=black!80!white] {};
    \end{tikzpicture}

\end{document}