Place the center hole of the protractor on the angle’s vertex
Align the protractor’s baseline with one ray of the angle
Make sure the vertex is centered on the protractor’s midpoint mark
Use the correct scale on the protractor
Read the degree mark where the other ray crosses the protractor
Measure from 0° on the aligned side
If the angle opens to the left, use the left 0° scale
If the angle opens to the right, use the right 0° scale
Mark the degree if needed
Remove the protractor carefully after reading the measurement