Answer:
1. D) 141°
2. B) 13
3. C) 20
Step-by-step explanation:
1.
Total angle: (7-2)×180 = 900
120 + 129 + X + 148 + 90 + 142 + 130 = 900
X = 900 - 759
X = 141°
2.
(n - 2) × 180 = 1980
n - 2 = 11
n = 13
3. Each exterior angle of a regular polygon is:
360/n
360/n = 18
n = 360/18
n = 20
