Angles on a Protractor - 4th Grade

Front

What is an angle?

Back

An angle is formed by two rays (sides) that share a common endpoint (vertex).

Front

What is a protractor used for?

Back

A protractor is a tool used to measure angles in degrees.

Front

What is the measurement of a right angle?

Back

90°

Front

What is the measurement of a straight angle?

Back

180°

Front

What is an acute angle?

Back

An acute angle is an angle that measures less than 90°.

Front

What is an obtuse angle?

Back

An obtuse angle is an angle that measures more than 90° but less than 180°.

Front

How do you read a protractor?

Back

To read a protractor, align the baseline of the protractor with one side of the angle and read the measurement where the other side intersects the numbered scale.

Front

What is the measurement of a full rotation?

Back

A full rotation measures 360°.

Front

If an angle measures 75°, what type of angle is it?

Back

It is an acute angle.

Front

If an angle measures 173°, what type of angle is it?

Back

It is an obtuse angle.