Answer:
a) 81
Step-by-step explanation:
Number of sides of the polygon = 6
Sum of angles of the polygon = ( n - 2) * 180
= (6 - 2) * 180
= 4 * 180
= 720
n = 720 - (110 + 108 + 143 + 122 + 156)
= 720 - 639
n = 81
