M2.5.4 For the adult
Measuring angles in degrees
How can I say how big an angle is, with a number?
What this chapter teaches
Angles are measured in degrees: a right angle is 90°, a straight line 180° and a full turn 360°. With a protractor, read the scale that starts at 0 on your arm, and check the number against a right angle.
Three questions to ask
There is no one right wording. Listen for the idea.
- How can you tell, before measuring, whether an angle is bigger or smaller than 90°?
- Why does a protractor have two scales, and how do you choose one?
- How many degrees do you turn if you turn a quarter turn three times?
After the chapter, the learner can
- Say a right angle is 90° and a full turn is 360°
- Measure an angle with a protractor
- Draw an angle of 60° with a protractor
What they copy into their notebook
A right angle is 90°. A straight line is 180°. A full turn is 360°. Put the protractor centre on the corner. Put its 0 line on one arm. Read the scale from 0.