GeoGebra Tool Bar
The main tools used to create geometric figures in GeoGebra are located in a horizontal tool bar of buttons at the top of the application window. Clicking once on any of these buttons reveals a drop-down list of menu items grouped into categories. For example, here we have clicked on the Line button and hovered over the Segment menu item (without clicking). Near the bottom of the screen you will notice that GeoGebra gives you an idea of what you have to select to create that object.

Lines and Segments
To illustrate the use of a tool in the Toolbar, we will create a line defined by two points. Click on the Line Button and then click somewhere in the window and drag. Notice that GeoGebra creates a point (A) where you first clicked and a second point(B) where you released the mouse. These define the line. Create another line, with points C and D. GeoGebra automatically labels any points we create and also creates a list of all of the properties of objects we create. This is the list at the left side of the window. Points are listed with their labels and lines with their linear equations.

Now, let's create a segment. Click on the Line Button and drag down to select the Segment menu item. Notice that the Line button now shows a segment icon. We have changed the functionality of the Line tool so that it is now a segment tool. This is a fundamental technique used in GeoGebra to provide for multiple tools with just a few buttons. With the Segment Tool now active, click and drag to create a segment. Segments are labeled with lower-case letters.