[tex]h=6 \ cm \\ a=2\sqrt{3} \ cm \\ \boxed{A_l-?}\\ A_l= \frac{P_b \cdot a}{2} \\ P_b=3l \\ a= \frac{l\sqrt{3}} {6} \\ \Rightarrow l= \frac{6a}{\sqrt3} = \frac{12\sqrt3}{\sqrt3} \\ l=12 \\ P_b=3 \cdot 12=36 \ cm \\ A_l= \frac{36 \ cm \cdot 2 \sqrt3 \ cm}{2} \\ \Rightarrow \boxed{A_l=36\sqrt3 \ cm^2}[/tex]
