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\begin{document}
\begin{center}
\Huge\sf \textbf{A proof of the sine sum-of-angles formula}
\end{center}

\bigskip

\begin{center}\large
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\node at(11.2,6.4){\begin{tabular}{c}Area of rhombus\\$=1\cdot\sin(x+y)$\end{tabular}};
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\smallskip

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\Large\bf Therefore \boldmath{$\sin(x+y)=\sin x\cos y+\cos x\sin y$}
\end{center}
\begin{center}\tiny 
Peter Jipsen -- Andrew Moshier -- math.chapman.edu/mathposters
\end{center}
\end{document}
