keeping in mind that regular polygon has 12 sides
[tex]\textit{area of a regular polygon}\\\\ A=\cfrac{1}{2}ans~~ \begin{cases} a=apothem\\ n=\stackrel{number~of}{sides}\\ s=\stackrel{length~of}{a~side}\\[-0.5em] \hrulefill\\ A=214.14\\ a=8.3\\ n=12 \end{cases}\implies 214.14=\cfrac{1}{2}(8.3)(12)s \\\\\\ 214.14=49.8s\implies \cfrac{214.14}{49.8}=s\implies 4.3=s[/tex]
