Investigating Mathematics with GeoGebra

Henrico County Public Schools

What are the measures of ∠´s A, B, and C ?

READ the instructions on the right and INTERACT with the GeoGebra applet below.

Sorry, the GeoGebra Applet could not be started. Please install Java 1.4 (or later) to use this page.

Investigation Steps

Click on the reset icon icon to reset the diagram.

 Step 1 Close 
  1. ∠A and the 120° angle are called a ______ pair?

  2. What is the measure of ∠A ?

  3. ∠B and the 10° angle are called ___________ angles?

  4. What is the measure of ∠B ?
 Step 2 Close 
  1. What is the sum of the 3 angles in a triangle?

  2. What is the measure of ∠C ?

  3. You can use the angle segment tool tool to shade the angles by clicking on the three points that name an angle in a clockwise order.
 Step 3 Close 
  1. Ctrl-click or right click the shaded angles.

  2. In the drop-down menu, select Properties.

  3. Find show label, use the pull-down menu next to it and select Value.

  4. Use this to check the angle measures you found by using angle properties.