Answered by : emily-baumgartner

\begin{equation} \label{eq1}
\begin{split}
A & = \frac{\pi r^2}{2} \\ & = \frac{1}{2} \pi r^2
\end{split}
\end{equation}

Source : https://www.overleaf.com/learn/latex/Aligning_equations_with_amsmath | Last Update : Tue, 06 Sep 22