Measuring Using a Protractor

Do you think this is a 85° angle?

• Yes

• No

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°.

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.

We should read the measurement based on the inner scale because '0' starts from the ______.

• inner scale

• outer scale

∠a = ______°

• 75

• 85

• 105

• 115

Which angle type is pictured?

• Acute

• Right

• Obtuse

• Straight

_{What is the measure of the angle?}

• 110 degrees. 

• 140 degrees.

• 150 degrees.

• 170 degrees. 

Angles are measured using a ______.

• compass

• protractor

• ruler

• prospector

_{What is the measure of the following angle?}

• 78 degrees.

• 11 degrees.

• 190 degrees.

• 58 degrees. 

Which angle type is pictured?

• Acute

• Right

• Obtuse

• Straight