Respuesta :

Answer:

1) x= 15

2) x= 34

3) x= 40

Step-by-step explanation:

1) 4x°= 45° +15° (vert. opp angles)

4x°= 60° (simplify)

x°= 60° ÷4 (÷4 on both sides)

x°= 15°

Thus, x= 15.

2) (x+12)° +100° +x°= 180° (adj. angles on a str. line)

2x° +12°= 180° -100°

2x°= 80° -12°

2x°= 68°

x°= 68° ÷2

x°= 34°

x= 34

3) 3x°= 120° (vert. opp. angles)

x°= 120° ÷3

x°= 40°

x= 40

Abbreviations:

1. vert. opp. angles

- vertically opposite angles

- This means that when 2 straight lines intersect, the angles facing opposite each other are equal.

2. adj. angles on a str. line

- adjacent angles on a straight line

- the sum of the angles that lie on a straight line is 180°