Protractors and measuring angles
Answers are for parents and teachers.
1
A paper circle is folded in half three times. How many equal angles do the folds make at the centre? How big is each one?
8 equal angles, each 360° ÷ 8 = 45°.
2
Describe in your own words where to put the centre mark and the baseline of the protractor when you measure an angle.
Put the centre mark on the vertex and the baseline exactly along one arm of the angle.
3
The two scales give 70° and 110° for an angle that looks obtuse. Which is the right reading? Why?
110°, because an obtuse angle is more than 90°.
4
Read the angle in the picture. The baseline is on the right arm.
About 85°, a little less than a right angle.
5
An angle falls between the 90° and 135° folds of your paper model. Write a number that could be its size and say whether it is acute or obtuse.
For example 110°. It is obtuse because it is more than 90°.