Angle Measurement Using Protractor

Which of the following measures is an example of acute angle?

• 90^o

• 89^o

• 100^o

• 95^o

• obtuse angle

• acute angle

• straight angle

• reflex ngle

What is the measure of the missing angle?

• 90

• 110

• 101

What is the measure of the missing angle?

• 39°

• 129°

• 119°

• 129°

Is this the correct way of using a protractor to measure an angle

• Yes, because the vertex of the angle is aligned with the center point of the protractor.

• No, because the baseline of the protractor is not aligned properly with the bottom ray of the angle.

This is the wrong way of using a protractor because __________.

• the bottom line of the angle is not aligned to the baseline of the protractor.

• the vertex of the angle is not aligned to the center point of the protractor.

Do you agree that ∠a = 90°.

• Yes. The top line of the angle is aligned to 90°.

• No. The measurement is not accurate because the bottom line of the angle is not aligned to the baseline of the protractor.

This is what kind of angle?

• obtuse

• right

• straight

• acute

Why is this not a 85° angle?

• 85° is an acute angle. The picture shows a right angle as it is 90°.

• 85° is an obtuse angle. The picture shows an acute angle as it is less than 90°.

• 85° is an obtuse angle.The picture shows an acute angle as it is less than 90°.

• 85° is an acute angle. This picture shows an obtuse angle as it is more than 90°.

The amount of the angle above is . . . .

• 60^o

• 80^o

• 120^o

• 140^o