What is the sum of the interior angles of a octagon

Question

anonymous · Answer

Sum of Interior Angles = (n-2) × 180°
where n is the number of sides
Here it is 8 ..So
Answer = (8-2) x 180°
            = 6 x 180°
            = 1080°

anonymous · Answer

$\Large \color{red}{Method\ 1} $
sum of interior angles of a polygon $\Large = (n – 2) × 180 $
in octagon number of sides $\Large n = 8 $
sum of interior angles $\Large = (8 – 2) × 180 = 1080$ 

$\Large \color{red}{Method\ 2}$ 
sum of exterior angles of polygon is always $\Large 360°$ 
and each exterior angle $\Large = 360/n = 360/8 = 45° $
so so each interior angle $\Large = 180 – 45 = 135° $
so sum of 8 interior angles $\Large = 8 × 135 = 1080° $