Measuring Angles on Protractors

We will read the measurement from the __________ scale.

• inner

• outer

Tags

CCSS.4.MD.C.6

Is this the correct way of using a protractor to measure angles?

• Yes

• No

Tags

CCSS.4.MD.C.6

∠DEF = ______°

• 34°

• °146

Tags

CCSS.4.MD.C.6

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

• Yes

• No

Tags

CCSS.4.MD.C.6

Do you think this is a 85° angle?

• Yes

• No

Tags

CCSS.4.MD.C.6

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°.

Tags

CCSS.4.G.A.1

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 centre of the protractor.

Tags

CCSS.4.MD.C.6

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.

Tags

CCSS.4.MD.C.6

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

• inner scale

• outer scale

Tags

CCSS.4.MD.C.6

∠a = ______°

• 75

• 85

• 105

• 115

Tags

CCSS.4.MD.C.6