Wednesday, January 2, 2013

GeoGebra Tutorial: How to Disable Reflex Angles

In GeoGebra, we use the Angle tool to reveal angle measures.  By default, an angle can measure  up to 360°; howeverthere are instances that we want it to be less than or equal to 180°.  For example, we need to limit the angle measures of the interior angles of a polygon to 180° if we want to find its angle sum. 

In this tutorial, we learn how to disable angles measuring more than 180° but less than 360°.  Such angles are called reflex angles.  To disable reflex angles, do the following:

1. Right click the angle measure (green sector) and click Object Properties to display the Preferences window.

2. In the Preferences window, click the Basic tab.
3. Select 0° and 180° in the Angle Between dialog box and then close the window. 


  1. Great tips and very easy to understand. This will definitely be very useful for me when I get a chance to start my blog Nissan 370Z Ironman Car