Answer:
11-12
180 = 4x + 30 + x + 15
180 = 5x + 45
5x = 135
x = 27
4(27) + 30 = 138 deg
27 + 15 = 42 deg
13-14
45 = 3x + 9
3x = 36
x = 12
3(12) + 9 = 45 deg
15-16
98 = angle 2 (vertical angles are the same)
angle 1 = 180 - 98
angle 1 = 82
angle 2 = 98
17-18
angle 4 = 121 deg (alternate exterior angles are the same)
angle 3 = angle 4
angle 3 = 121 deg (vertical angles are the same)
19. angle 1 = 180 - 42 = 138
20. angle 3 = angle 1 = 138 (corresponding angles are the same)
21. angle 4 = angle 2 = 42 (corresponding angles are the same)
22. angle 5 = angle 1 = 138 (alternate exterior angles are the same)
23. angle 6 = angle 2 = 42 (alternate interior angles are the same)
24. angle 7 = angle 1 = 138 (vertical angles are the same)
25. angle 8 = angle 2 = 42 (vertical angles are the same)
