Place the center hole of the protractor on the angle’s vertex
Align one side of the angle with the protractor’s baseline
Check which scale starts at 0 on the aligned side
Read the number where the other side of the angle crosses the scale
Use the inner scale if the left side is aligned with 0
Use the outer scale if the right side is aligned with 0
Make sure you read the correct scale for the angle’s direction
Record the angle measurement in degrees
Verify the reading by checking that it matches the angle’s opening