- Jack D. Gittinger
Step 1. Construct One the GeoGebra page you will see four geometric objects: 1. Point A 2. Point B 3. Point C 4. Line BC On the Tool Bar there is a PERPENDICULAR LINE tool .Click on the PERPENDICULAR LINE tool to select it. Notice the instructions for this GeoGebra tool: Click first on Point A and then click on Line BC. This will create a new, perpendicular line. But just what is a “perpendicular line?” Step 2. Experiment Use the MOVE tool to experiment by moving Points A, B, or C. Move the two lines as well. Make observations. If needed, use the ZOOM IN or ZOOM OUT tool to change your view. Step 3. New Construction Use the DELETE OBJECT tool to click on all the points and lines on the GeoGebra page and delete them. Now use the NEW POINT tool , the LINE THROUGH TWO POINTS tool , and the PERPENDICULAR LINE tool to create your own perpendicular lines and again experiment by moving points or lines. Step 4. Conclusions So just what is a perpendicular line? Share your conclusions with your teacher.