Question

Find the sum of the interior angles for an octagon.

1,080°
1,260°
1,440°
1,620°

Answer 1

What the person said above me

Answer 2

`\underset{in~degrees}{\textit{sum of all interior angles}}\\\\ S = 180(n-2) ~~ \begin{cases} n=\stackrel{number~of}{sides}\\[-0.5em] \hrulefill\\ n=\stackrel{octagon}{8} \end{cases} \implies S=180(8-2)\implies S=1080`