Measuring Angles With a Protractor

A precise angle measurement has high significance in geometry and has various practical applications. Measuring angles with a protractor provides a precise value of angles and helps mathematicians, engineers, and navigators to draw angles on blueprints.  

In mathematical terms, an angle is formed when two rays meet each other on a single point. The point on which two rays meet is known as the vertex of the angle. The angles are represented by “∠”.

What is a Protractor?

A protractor is a geometrical tool for measuring angles that helps engineers to precisely measure, and draw them. It is a semi-circular tool marked with degrees 0-180. The degrees on the Protractors are written in two ways i.e. from left to right and right to left. We can measure angles from 0-360 with this tool. 

How to Use the Protractor

We can find any angle by using a protractor. Let’s know how to use the protractor in easy steps. 

1. Place the midpoint (center marker) exactly on the vertex (where the two lines meet to form an angle).
2. One of the lines of an angle must align with the zero on the protractor.
3. The protractor reading will let you know about the measurement from that ray lined up with the protractor’s baseline.

Measurement of Angles Using Protractors

Sometimes we can measure an angle without a protractor just looking at it. For example, a straight vertical ray shows 90 degrees, and a straight horizontal rays show 180 degrees. However, for precise measurement of angles, protractors are much needed. 

Let’s look at some of the examples of measuring angles using protractors.     

Example 1:

Consider we have angle ∠ABC. To find the exact angle, we will follow the above-mentioned steps.

Steps  

• Place the center marker of the protractor on the vertex B.
• Align ray BC with the 0 on the protractor.
• Read the measurement from the right side. 
• The point where ray AB meets with the reading of the protractor is the angle of ∠ABC.

Thus ∠ABC= 45°

Example 2:

We will look at some more measuring angles examples here. 

Consider we have an angle ∠POQ.

To find the measurement of an angle ∠POQ in degrees we will follow these simple steps.

Steps 

• Place the midpoint of the protractor on the vertex O.
• Align ray OQ with the 0 on the protractor.
• Read the measurement from the right side. 
• The point where ray PO meets with the reading of the protractor is the angle of ∠POQ

Thus ∠POQ= 140°

Measuring Angles Using a Protractor Worksheet

Worksheets help students understand the measurements by practicing them. Here we help you by providing measuring angles using a protractor worksheet. Practice finding the degree of each angle and fortify your measuring skills.