There are several angle relationships in a parallel line cut by transversals. Any two angles can either be congruent or supplementary.
The following angles are congruent:
- Correnponding angles:
- ⦣1≅⦣5
- ⦣3≅⦣7
- ⦣2≅⦣6
- ⦣4≅⦣8
- Alternate interior angles:
- ⦣3≅⦣6
- ⦣4≅⦣5
- Alternate exterior angles:
- ⦣1≅⦣8
- ⦣2≅⦣7
- Vertical angles
The following angles are supplementary (meaning their measure add up to 180o)
- Same side exterior
- m⦣1 + m⦣7 = 180o
- m⦣2 + m⦣8 = 180o
- Same side interior
- m⦣3 + m⦣5 = 180o
- m⦣4 + m⦣6 = 180o
- Linear pair
So here are the answers:
- m⦣1 = 105o because it is ⦣1 and ⦣3 are linear pair.
- m⦣2 = 75o because it is ⦣2 and ⦣3 are vertical angles.
- m⦣3 = 75o given.
- m⦣4 = 105o because ⦣4 and ⦣3 are linear pair.
- m⦣5 = 105o because ⦣3 and ⦣5 are same side interior angles.
- m⦣6 = 75o because ⦣3 and ⦣6 are alternate interior angles.
- m⦣7 = 75o because ⦣3 and ⦣7 are corresponding angles.
- m⦣8 = 105o because ⦣2 and ⦣8 are same side exterior angles.