Proportional segments of parallel lines

Move any blue point and notice the change in the ratios of the sides. Note how this is developed from the original triangle proportionality theorem that is displayed at first. Click the top checkbox to see the third parallel segment. You can see the original ratios from the triangle proportionality theorem with the second and third checkboxes along with the new ratios from the third parallel line.
Jerel L. Welker and Matt James Lincoln Southwest HS Lincoln, NE and