1. How to Use a Protractor

2. This presentation is designed to teach you how to use a protractor to measure angles.
It will also teach you how to use your protractor to create an angle at a specific measurement.

3. Examining Your Protractor
Although these protractors may look the same, they actually work differently.
To determine which type of protractor you have, you must find the “Zero Line” and the “Vertex Point”.

4. The zero line on this protractor is the bottom edge.
Finding the Zero Line
You can find the Zero Line by connecting the zero degree marks on the left and right sides of the protractor.
Zero Degree Mark #1
Zero Degree Mark #2
The zero line on this protractor is the bottom edge.

5. The zero line on this protractor is n o t the bottom edge.
Zero Degree Mark #2
Zero Degree Mark #1
The zero line is marked in black on the protractor.

6. Finding the Vertex Point
The vertex point is the point on the protractor where you must place the vertex of an angle in order to measure or create the angle. It is located at the center of the zero line directly below the 90 degree mark.
VERTEX POINT
VERTEX POINT

7. MEASURING an ANGLE
STEP 1:When measuring an angle you need to first place the vertex point of the protractor on the vertex of the angle.
STEP 2:With the vertex point remaining over the vertex, you need to rotate the protractor so that the zero line is over one of the rays of the angle.

8. MEASURING an ANGLE
STEP 3:When the vertex point is aligned with the vertex and the zero line is over one of the rays, you can now measure the angle.
Most protractors will have two scales. One runs from the left zero to the right zero along the outside ring and the other runs from the right zero to the left zero along the inside ring.

9. Inner and Outer Degree Scales
For measuring angles opening from the right use the inside scale 0 ° °
For measuring angles opening from the left use the outside scale 0 ° °

10. Since our angle opens from the right side we will use the inner scale.
MEASURING an ANGLE
Since our angle opens from the right side we will use the inner scale.
STEP 4:Determine where the ray of the angle crosses the inner degree scale.
What is your reading for these angles???
Click on the button when you have your answer.

11. 63°
63°
63°
63°
63°
63°
63°
63°
63°
63°
63°

12. How to Draw an Angle with a Protractor
STEP 1:You must start with one ray and a vertex for your angle.

13. How to Draw an Angle with a Protractor
STEP 2:Place the protractor over the line so that the vertex point is on the angle vertex and the ray is on the zero line.

14. How to Draw an Angle with a Protractor
STEP 3:Using the correct scale (inside or outside) place a mark at the desired degree. (example 110°)

15. How to Draw an Angle with a Protractor
STEP 4:Remove the protractor and connect the vertex of your angle with the mark. Add an arrow to create the second ray of the angle.
110°