[tex]\textit{sum of all interior angles in a polygon}\\\\ n\theta = 180(n~~ - ~~2) \begin{cases} n=\stackrel{\textit{number of}}{sides}\\ \theta =\stackrel{degrees}{angle}\\[-0.5em] \hrulefill\\ n=26 \end{cases}\implies (26)\theta =180(26~~ - ~~2) \\\\\\ 26\theta =180(24)\implies 26\theta =4320\implies \theta =\cfrac{4320}{26}\implies \theta \approx 166.15^o[/tex]
