• Share

### Your suggestion is on its way!

An email with a link to:

was emailed to:

Thanks for sharing About.com with others!

##### Most Emailed Articles

&quot;Big Five&quot; Personality Quiz

Geometry Course
Measuring Angles - Part 4
 Free Geometry Basics Course •Part 1 Terms in Geometry •Part 2 Types of Angles •Part 3 •Postulates • Part 4 • Measuring Angles • Part 5 • Bisectors, Congruencies, Theorems • Part 6 •Transversals • Geometry Help • Mathematicians Review • Conic Sections • Pythagorean Theorem
 Related Resources • Measurement Formulas • Recommended Resources • Area Calculator • Introduction to Polygons

The size of an angle will depend on the opening between the two sides of the angle (Pac Mac's mouth) and is measured in units that are referred to as degrees which is indicated by the ° symbol. To help you remember approximate sizes of angles, you will want to remember that a circle, once around measures 360°. To assist you to remember approximations of angles, it will be helpful to remember the following:

Think of a whole pie as 360°, if you eat a quarter (1/4) of it the measure would be 90°. If you ate 1/2 of the pie? Well, as stated above, 180° is half, or you can add 90° and 90° - the two pieces you ate!

If you cut the whole pie into 8 equal pieces. What angle would one piece of the pie make? To answer this question, you can divide 360° by 8 (the total by the number of pieces). This will tell you that each piece of pie has a measure of 45°.

Usually, when measuring an angle, you will use a protractor, each unit of measure on a protractor is a degree °.
Note: The size of the angle is not dependent on the lengths of the sides of the angle.

In the above example, the protractor is used to show you that the measure of angle ABC is 60°

Try a few best guesses, the angles below are approximately 10°, 50° , 150°,