Begin with two lines that intersect at Q. We plan to measure angles
JQM and LQK and verify the angles are the same. 

Step 1 
Place the protractor so that the origin (small hole) is over the point Q. 

Step 2 
Rotate the protractor so that the base line is exactly along the line JK. 

Step 3 
Using the inner scale, read the angle over the line LM. It should read 34 degrees.
This shows that the angle ∠LQK has a measure of 34°. 

Step 4 
Now, rotate the protractor so that its base line is along the line LM 

Step 5 
Using the outer scale, read the angle over the line JK. It should read 34 degrees,
showing that the angle ∠JQM also has a measure of 34°. 

Step 6 
Done. By measuring these two angles, you have verified that
vertical angles are
congruent. 
