Measure Angles using a Protractor
Videos, stories and songs to help Grade 4 to Grade 6 students learn how to measure angles in degrees using a protractor.
More Lessons for Grade 6
A degree is the unit used to measure rotation within a circle
and can be used to measure angles. The measure of rotation for a full turn within a
circle will always be 360°. This is true regardless of the size (diameter) of
You can construct your own 360° protractor using a circular
piece of paper.
• A circle
(full turn) has a measure of 360°.
• Fold the circle in half. If a full circle
measures 360°, a half of a circle must
• Fold the half circle in half again. This
represents a quarter of the whole circle. If half
of the circle measures 180°, a quarter must
• Fold the quarter circle in half again. This
represents an eighth of the whole circle. If a
quarter of the circle measures 90°, an eighth
must measure 45°.
• Unfold the circle. There should be eight sets of 45° in the whole. Choose a fold line as
0°; label each fold line in the counterclockwise direction as a consecutive multiple of 45°, as shown below.
When measuring angles using a protractor it is important that the
reading always begins at zero. Do not make the mistake of beginning at the 180° mark. You
must always line up one arm of the angle with the zero degree and then
begin counting up from zero until they reach the next arm. This will
avoid incorrect scale readings. The degrees on the protractor are only labeled in multiples of
ten, however each unlabeled tick represents 1°. The center point of
the protractor must be placed on the vertex of the angle and the zero
degree mark of the protractors baseline must be lined up with one of the
Some protractors have an inner scale and an outer scale. It is important to recognize that the direction of rotation between
angle arms to determine which scale is used on the protractor. Always line up the zero degree with the first arm of the angle and count
up to the next arm to avoid any confusion with regard to which scale
should be used. The arc (hatch mark) between the
arms of the angle indicates which angle is being measured.
The following diagram shows how to measure the angle ∠ABC using a protractor.
How to measure angles using a protractor
Use a full circle or half circle protractor to learn to measure angles.
How to use a protractor.
Measuring Angles with a Protractor.
How to measure an angle with a protractor.
How to use a protractor to measure and draw angles.
How to Use a Protractor to Measure Angles.