Constructing a Right Angle Triangle using The Geometer’s Sketchpad

1.	If you create your triangle on a grid, you will find that this is a very easy way to produce a right triangle. You can show the grid by selecting the Graph menu, Grid Form, Square Grid. This option is a toggle; meaning that it is either on, indicated by the  or off. 

2.	 In addition, for accuracy you should also select the Snap Points option under the Graph menu.  

	

3.	 Select the Point Tool  and create 3 points. These will serve as the vertices for your triangle.

	

4.	Now you are ready to connect all 3 vertices with line segments. With the Selection Arrow Tool select all 3 vertices. Once these are highlighted, go to the Construct menu and choose Segments. You should now see your right-angled triangle!

	

5.	It is important to understand that the triangle you have constructed does not have a fixed right angle. This means that you can move the upper vertex to the next grid line, and the angle will no longer be 90º.
Be aware of this if you need to move your triangle for any reason.