Let m = measure of each interior angle of a regular polygon
It turns out that
m = [180*(n-2)]/n
where n is the number of sides
We have n = 9 sides, so
m = [180*(n-2)]/n
m = [180*(9-2)]/9
m = [180*7]/9
m = 1260/9
m = 140
Each interior angle is 140 degrees
Answer: D) 140
