sample_circle.tex
\documentclass{amsart}
\usepackage{bigcircle}
\begin{document}
\begin{Huge}The bigcircle Package\end{Huge}\\[3mm]
Just include the statement $\backslash$usepackage\{bigcircle\} in
the header, then use\\
$\backslash$bigcircle\{\textit{x-value of center}\}\{\textit{y-value of center}\}\{\textit{radius}\}\\
to add a circle. It must be used in math or picture modes. This is a circle with radius 1 inch:
\setlength{\unitlength}{1in} $$\bigcircle{0}{0}{1}$$
This is a circle with radius 4.3 cm:
\setlength{\unitlength}{1cm} $$\bigcircle{0}{0}{4.3}$$
\end{document}