Answer:
1. 180°
2. m∠AOB
3. 60° + 90 ° + 30 ° = 180 °
4. x = 15
Step-by-step explanation:
Reason for number 1:
All straight lines are 180°
Reason for number 2:
These angles all add up to 180° and the line with this angle is m∠AOB.
