Labeling certain objects is important in communicating ideas in mathematics, especially
if you are working on a geometry problem.
Text-boxes can be very useful for labeling objects on the board. You can also use
special math notations to label angles, edges etc. (check this link for more info about
math symbols).
Click here to watch a movie clip showing how to use text boxes to label objects.
Here is another example:
Suppose that you want to label the top right corner of the red rectangle in the figure
below with letter "C"
1. Click on the text box icon .
(The pointer should look like a plus sign now)
2. Click on the place where you want to put your text box (see figure below)
3. You will see a small yellow text box with the cursor activated inside (see figure
below)
4. Type "C" inside the box
5. To post your label, click on somewhere outside the text box. This will make your
label visible to the rest of your group.
.
(The pointer should look like a plus sign 
now) 
