[tex] \bf \begin{array}{|c|ll}
\cline{1-1}
\textit{area of a triangle}\\
\cline{1-1}
\\
A=\cfrac{1}{2}bh~~
\begin{cases}
b=base\\
h=height
\end{cases}
\\\\
\cline{1-1}
\end{array}~\hspace{7em}
\begin{array}{|c|ll}
\cline{1-1}
\textit{area of a square}\\
\cline{1-1}
\\
A=s^2\qquad
\begin{array}{llll}
s=length~of\\
\qquad a~side
\end{array}
\\\\
\cline{1-1}
\end{array} [/tex]
