# GeoGebra Tutorial: How to Disable Reflex Angles

In GeoGebra, we use the

*tool to reveal angle measures. By default, an angle can measure up to 360***Angle***°;*however*,*there 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.