1. Using a Protractor
Geometry Lesson

3. A 180o Protractor
Outside scale from o to 180o going in a clockwise direction.
Inside scale from o to 180o going in an anti-clockwise direction.

4. You need to be able to measure an angle to the nearest degree
You need to be able to measure an angle to the nearest degree. To help you do this you should always:
1. Look directly down onto the cross point.
2. Always use the protractor in a horizontal manner as shown below. 
12-Nov-18

5. Measuring Angles with a Protractor
Place the center point of the protractor on the vertex of the angle.

6. Measuring Angles with a Protractor
Read where the top ray crosses the protractor. (Identifying your angle as acute or obtuse will help you know whether to use the top or bottom set of numbers)

7. Measuring Angles with a Protractor
Therefore this angle has a measure of 50°

8. Measuring Angles with a 180o Protractor2
0 on the inside so use inside scale
67o
0 on the outside so use outside scale

9. Measuring Angles with a 180o Protractor 120o3
Measuring Angles with a 180o Protractor
120o 4
0 on the inside so use inside scale
135o
0 on the outside so use outside scale

10. Drawing Angles with a Protractor
The first step should be to extend the rays that form the angle using a straight edge or a ruler.

11. ACTIVITY 1.
Using a protractor, draw the following angles with the given measures.
1. 85°
2. 15°
3. 140°

12. REFERENCE:
12-Nov-18

13. ACTIVITY 2. CLASSIFICATION OF ANGLES