Question

If $S$ denotes the sum of all the interior angles of a polygon of $n$ sides, then the number of right angles in $S$ is:

• A. $(n-1)$
• B. $2(n-1)$
• C. $2(n-2)$
• D. $2n$

Answer 1

The correct option is C $2(n-2)$

$s=$ Sum of the interior angles of a polygon of $n$ sides
$=(n-2)\times {180}^o=2(n-2)\times {90}^o$
$=2(n-2)$ right angles.