Answer:
40 degrees
Explanation:
The formula for calculating the sum of interior angles is ( n − 2 ) × 180 (n = Number of sides)
in this scenario you have 9 sides so put it in the equation.
(9 - 2) ×180 = 1260
1260 is the sum of all the interior angles so we must divide this number by the number of sides to get the angle of one individual interior angle.
1260/9 = 140
180-140 = 40 degrees