Printable instructions for measuring an angle using a protractor

Measuring an angle using a protractor

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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.

Measuring an angle using a protractor