Area of Parallelogram by dissection

This application is intended to help students discover the formula for the area of a parallelogram. 1) You can change the size of your parallelogram by moving the point C around and moving the middle slider, slider l, from side to side. 2) Once you have picked a parallelogram, slide the slider g all the way to the right. This cuts off a triangle from the parallelogram and moves it to create a rectangle. 3) The area of the rectangle will appear in the center. How do you think this is related to the area of the original parallelogram? 4) Move slider g back to the left to form the parallelogram again. Now move slider f to the right. This reveals the area of the parallelogram. Was your guess correct? 5) How can you use this to develop the rule for the area of a parallelogram with base B and height H?