Answer: See explanation
Explanation:
10) Same side interior angles add up to 180°
3x + x = 180
4x = 180
x = 45
11) Same side interior angles add up to 180°
5x + 3x = 180
8x = 180
x = 22.5
12) 6x is vertical to an angle that has a relationship with 3x (same side interior angles) which means 6x and 3x have to add up to 180° as well
6x + 3x = 180
9x = 180
x = 20