Measuring Angles using 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 side of the angle intersects the numbered scale.

Front

What is the measure of a right angle?

Back

A right angle measures 90 degrees.

Front

What is the measure of an acute angle?

Back

An acute angle measures less than 90 degrees.

Front

What is the measure of an obtuse angle?

Back

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

Front

What is a straight angle?

Back

A straight angle measures exactly 180 degrees.

Front

If an angle measures 45 degrees, what type of angle is it?

Back

It is an acute angle.

Front

If an angle measures 120 degrees, what type of angle is it?

Back

It is an obtuse angle.

Front

What is the sum of angles in a triangle?

Back

The sum of angles in a triangle is always 180 degrees.

Front

How do you find the measure of an unknown angle?

Back

To find the measure of an unknown angle, you can subtract the sum of the known angles from 180 degrees.