Pi by Ramanujan

$$\begin{align}
\frac{9}{5}\;+\;\sqrt{\frac{9}{5}}\;&=\;|\overline{AB}|+|\overline{AC}| \\
&=\;|\widehat{AB^\prime}|+|\widehat{AC^\prime}| \\
&\approx\;|\stackrel{\frown}{AB^\prime}|+|\stackrel{\frown}{AC^\prime}| \\
&=\;|\stackrel{\frown}{B^\prime C^\prime}| \\[4pt]
&\approx\;\pi
\end{align}$$