Question

The sum of the interior angles of an octagon is equal to ___

• A. 8 right angles
• B. 9 right angles
• C. 10 right angles
• D. 12 right angles

Answer 1

The correct option is D

12 right angles

Sum of interior angles of a polygon with n sides = $(n-2)\times {180}^{\circ }$
An octagon has 8 sides (n = 8)

$\therefore$ Sum of interior angles of an octagon $=(8-2)\times {180}^{\circ }$ = $6\times 2\times 90$
( writing 180 as $2\times 90$)

$=12\left({90}^{\circ }\right)$

= 12 right angles