Arsir Daerah Persegi-1

\begin{tikzpicture}[scale=1,font=\small,line join=round]
\coordinate[label=below:\$ A\$] (A) at (0,0);
\coordinate[label=below:\$ B\$] (B) at (7,0);
\coordinate[label=above:\$ C\$] (C) at (7,7);
\coordinate[label=above:\$ D\$] (D) at (0,7);
\draw[very thick,bistre] (A)--(B)--(C)--(D)--cycle;
\end{tikzpicture}