keeping in mind that the diameter is 20m, so the radius is half that or 10m.
[tex]\textit{area of a circle}\\\\ A=\pi r^2~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=10 \end{cases}\implies A=\pi (10)^2\implies A=100\pi \\\\\\ \stackrel{\textit{at \$83 per metre}}{(83)(100\pi )\implies 8300\pi ~~~~\approx~~} \stackrel{\$}{26075.22}[/tex]
