Hopefully this sounds smart...<span>If the drawing of your octagon (or whatever) has been separated into triangles, and one triangle's </span>area<span> is labeled, then you do not need to know the apothem. Just take the </span>area<span> of that one triangle, and multiply by the number of sides in the original</span>polygon<span>.</span>
Find<span> the length of the sides plus the the</span>apothem<span>. Solution: Plug in what you know into both the </span>area<span> and the perimeter formulas to solve for the length of a side and the </span>apothem<span>.</span>
