1. Move the points indicated in the following picture to change the shape and size of the right triangle.
  2. Move, from left to right, the points corresponding to each proof step.
  3. Observe the changes in the diagram and draw conclusions.

Remark: After dragging a point from a slider, you may find yourself not able to deselect it. If such a situation occurs (which should be sporadic), just double click on the selected point.