Measuring Angles Using a Protractor

Front

We will read the measurement from the __________ scale.

Back

outer

Tags

CCSS.4.MD.C.6

Front

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

Back

Yes

Tags

CCSS.4.MD.C.6

Front

∠DEF = ______°

Back

34°

Tags

CCSS.4.MD.C.6

Front

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

Back

No

Tags

CCSS.4.MD.C.6

Front

Is this an 85° angle?

Back

No

Tags

CCSS.4.MD.C.6

Front

Why is this not a 85° angle?

Back

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

Tags

CCSS.4.G.A.1

Front

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.

Back

the vertex of the angle is not aligned to the centre of the protractor.

Tags

CCSS.4.MD.C.6

Front

Do you agree that ∠a = 90°?

Back

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

Front

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

Back

inner scale

Tags

CCSS.4.MD.C.6

Front

∠a = ______°

Back

75

Tags

CCSS.4.MD.C.6