Will do first question of each concept only because the rest of the questions are the same concept (the same few repeat but whatever).
1. <em>Total angle = (n - 2) * 180 --> 4 * 180 = 360°</em>
<em>70 + 130 + 120 + θ = 360</em> --> 320 + θ = 360 --> θ = 40
4. Total angle =<em> (10 - 2) * 180</em> --> 8 * 180 = <em>1440</em>
<em>1440/10</em> = 144°
6. Interior: (n - 2) * 180 --> 10 * 180 = 1800
Exterior: 12 * 180 = 2160 --> 2160 - 1800 = 360
9. (n - 2) * 180 --> 3 * 180 = 540
90 + 90 + 150 + 160 + θ = 540 --> 490 + θ = 540 --> θ = 50
13. Interior: (n - 2) * 180 --> 2 * 180 = 360
Exterior: n * 180 - (n - 2) * 180 --> 180n - 180n + 360 --> 360 (always the same)
16. 7r + 4r + 8r + 5r = 360 --> 24r = 360 --> r = 15
Answer:c
15x - 4
Step-by-step explanation:
15x - 4
