\begin{tikzpicture}[scale=2]
\clip (-0.1,-0.2)
rectangle (1.8,1.2);
\draw[step=.25cm,gray,very thin]
(-1.4,-1.4) grid (3.4,3.4);
\draw (-1.5,0) -- (2.5,0);
\draw (0,-1.5) -- (0,1.5);
\draw (0,0) circle (1cm);
\filldraw[fill=green!20!white,
draw=green!50!black]
(0,0) -- (3mm,0mm)
arc (0:30:3mm) -- cycle;
\end{tikzpicture}