Question

What will be the sum of interior angles of a polygon with 9 sides :

Answer 1

Number of sides n = 9
The sum of interior angles of polygon $=(2n-4)\times {90}^{\circ }$
$=(2\times 9-4)\times {90}^{\circ }=(18-4)\times {90}^{\circ }=14\times {90}^{\circ }$
We get,
$={1260}^{\circ }$.