Skip to main content
Search IntMath
Close

450+ Math Lessons written by Math Professors and Teachers

5 Million+ Students Helped Each Year

1200+ Articles Written by Math Educators and Enthusiasts

Simplifying and Teaching Math for Over 23 Years

Tips, tricks, lessons, and tutoring to help reduce test anxiety and move to the top of the class.

Everything You Need to Know About Reflex Angles 

If you’ve ever taken a geometry class, chances are you’ve heard of reflex angles. But what exactly is a reflex angle? In this blog post, we’re going to explain the basics of reflex angles and why they’re important in math. 

What is a Reflex Angle? 

A reflex angle is an angle that measures more than 180 degrees but less than 360 degrees. It can also be defined as an obtuse angle, or an angle with more than 90 degrees but less than 180 degrees. Reflex angles look like the letter “C” and are measured counterclockwise from 0 degrees or the x-axis.  

Where Are They Used?   

Reflex angles are used all over geometry, from basic shapes to complex equations. For example, when drawing a triangle, one of the angles must be larger than 90 degrees—otherwise it wouldn’t be a triangle! This means that if you want to draw a triangle with three sides of equal length (an equilateral triangle), one of the three angles has to be greater than 90 degrees—in other words, it has to be a reflex angle! Similarly, when finding the area of polygons with many sides (like hexagons or octagons), it often requires measuring those interior and exterior angles before being able to calculate the area accurately. In short, understanding how to measure and use reflex angles is essential for anyone studying geometry. 

How Do You Measure Them?             

Measuring reflex angles is easy once you know how! Simply place your protractor so that its base line lines up with one side of the angle and then rotate it until the other side lines up with another degree mark on your protractor. Then all you have to do is read off which degree mark corresponds with this second side—that will give you your answer! You can also use a compass and ruler to measure reflex angles if you don't have access to a protractor. Just draw two rays extending from one endpoint of your angle and measure them using your compass; then use your ruler to connect them at their endpoints and draw in your third ray! Once again, simply measure this third ray using your compass and that will tell you what degree mark corresponds with this third side—and give you your answer!  

Conclusion:                                                                                                       

In summary, reflex angles are obtuse angles (angles greater than 90°) that measure between 180° and 360° when measured counter-clockwise from 0° or the x-axis. Understanding how these special types of angles function can help students studying geometry better understand concepts such as measuring polygons and triangles as well as calculating areas accurately. With some practice measuring these special types of angles using either rulers or protractors, students should have no problem mastering their knowledge of reflex angles in no time!

FAQ

Why is it called a reflex angle?

A reflex angle is so named because it looks like the letter “C” when measured counterclockwise from 0 degrees or the x-axis.

What is reflex angle formula?

The reflex angle formula is simply the degree measure of the angle, which is between 180° and 360° when measured counter-clockwise from 0° or the x-axis.

24x7 Tutor Chat

Tips, tricks, lessons, and tutoring to help reduce test anxiety and move to the top of the class.