Question

A. 15
B. 125
C. 135
D. 45

Answer 1

9x + 3x = 180°
12x = 180°
x = 15°

9x + 1 = 180°
9(15°) + 1 = 180°
135° + 1 = 180°
1 = 180° - 135° = 45°
Answer is D

Hope it helped!

Answer 2

The angle adjacent to 9x and on same lime as the angle 3x = 3x.
They are corresponding angles)

so 3x + 9x = 180

x = 180/12 = 15
So angle 1 = 3x = 3*15 = 45 degrees


D