now, is an equliateral triangle, so all sides are equal, if one side is 4ft, all three sides are 4ft.
[tex]\bf \textit{area of an equilateral triangle}\\\\ A=\cfrac{s^2\sqrt{3}}{4}~~ \begin{cases} s=length~of\\ \qquad a~side\\[-0.5em] \hrulefill\\ s=4 \end{cases}\implies A=\cfrac{4^2\sqrt{3}}{4}\implies A=4\sqrt{3}[/tex]
