Reading a Protractor

Front

What is a protractor?

Back

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

Front

How do you read a protractor?

Back

To read a protractor, align the baseline of the angle with the zero line of the protractor and read the degree measurement where the other ray intersects the numbered scale.

Front

What is the vertex of an angle?

Back

The vertex of an angle is the point where the two rays meet.

Front

What is an acute angle?

Back

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

Front

What is a right angle?

Back

A right angle is an angle that measures exactly 90 degrees.

Front

What is an obtuse angle?

Back

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

Front

What is a straight angle?

Back

A straight angle is an angle that measures exactly 180 degrees.

Front

What is the purpose of the inner scale on a protractor?

Back

The inner scale on a protractor is used to measure angles that open to the left.

Front

What is the purpose of the outer scale on a protractor?

Back

The outer scale on a protractor is used to measure angles that open to the right.

Front

How do you find the measurement of an angle using a protractor?

Back

Place the protractor's center point at the vertex of the angle, align one ray with the zero line, and read the measurement where the other ray crosses the scale.