Find the sum of the interior angles of a nonagon.

We know that a nonagon has 9 sides.

Therefore, n = 9

Sum of interior angles $=(n-2)\times {180}^o$

$=(9-2)\times {180}^o$

$=7\times {180}^o$

$={1260}^o$

Therefore, the sum of the interior angles of a nonagon is ${1260}^o.$