[tex]\textit{height of an equilateral triangle}\\\\ h=\cfrac{s\sqrt{3}}{2}~~ \begin{cases} s=\stackrel{side's}{length}\\[-0.5em] \hrulefill\\ h=12 \end{cases}\implies 12=\cfrac{s\sqrt{3}}{2}\implies 24=s\sqrt{3}\implies \cfrac{24}{\sqrt{3}}=s \\\\[-0.35em] ~\dotfill[/tex]
[tex]\textit{area of an equilateral triangle}\\\\ A=\cfrac{s^2\sqrt{3}}{4}\qquad \qquad A=\cfrac{~~ \left( \frac{24}{\sqrt{3}} \right)^2 \sqrt{3}~~}{2}\implies A=\cfrac{~~ \frac{24^2}{3} \sqrt{3}~~}{2} \\\\\\ A=\cfrac{192\sqrt{3}}{2}\implies A=96\sqrt{3}\implies A\approx 166.28[/tex]
