Answer:
BELOW
Explanation:
EXTERIOR ANGLES of any polygon sum to 360 degrees
there are 9 of them in this 9 - gon so each is 40 degrees
interior angles allows you to label the other angle as 40 °
Sum of INTERIOR angles of n-gon : (n-2 ) * 180° = (9-2)180° = 1260°
so EACH is 1260° / 9 = 140°
so angle at A plus 40° = 140° then angle at A = 100°