In these lessons, we will learn

- what is a protractor.
- how to measure angles using a protractor.
- how to draw angles using a protractor.

Interactive activities are included to help you practice measuring angles with a protractor.

**Related Pages**

Types Of Angles

Angles

More Geometry Lessons

The size of an angle is usually measured in degrees (°). Think of a circle which is divided into 360 equal sectors. Each sector has a small angle at the center of the circle – the size of such angle is 1 degree (written: 1°). In other words, the size of an angle is a measure of how wide the angle is at the vertex bound by the two sides.

Given an angle ABC,

How do we measure the size of the angle? We can measure angles using an instrument known as
a **protractor**.

A protractor is an instrument used to measure the size of angles.

The protractor shown below has two scales:

The outer scale starts from 0˚ to180˚ going clockwise.

The inner scale starts from 0˚ to 180˚ going anti-clockwise.

To measure angle **ABC** , we need to:

Step 1: Place the center point of the protractor on the vertex **B**.

Step 2: Adjust the base line of the protractor so that it is aligned with
the line **BC**

Step 3: Read the value of angle **ABC**, from the inner scale.

We can also adjust the base line of the protractor so that it is aligned with the
line **AB** and use the outer scale to measure the angle.

The following videos will show you how to measure and draw angles using a protractor.

**Measuring and Drawing Angles**

How to measure angles and draw angles using a protractor?

**Measuring angles using a protractor (acute angles)**

**Measuring Angles with Protractors (obtuse angles)**

Measuring Angles

Practice lining up and reading a protractor while you measure a set of angles in this fun learning activity.
The angles may range from 0° to 180°.

Try the free Mathway calculator and
problem solver below to practice various math topics. Try the given examples, or type in your own
problem and check your answer with the step-by-step explanations.

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