Menggambar Busur

\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;

%busur-busur
\draw[very thick,bistre,name path=BD] (B) arc (0:90:7cm);%busur ABD
\draw[very thick,bistre,name path=AC] (A) arc (180:90:7cm);%busur BAC
\end{tikzpicture}