1) Given that an equilateral triangle has three congruent sides, so we can tell that each side has the following measurement:
[tex]\begin{gathered} P_{\Delta}=l+l+l\Rightarrow P_{\Delta}=3l \\ 3l=36 \\ \frac{3l}{3}=\frac{36}{3} \\ l=12" \end{gathered}[/tex]Note that since they are congruent then we can tell that.