If you're going to teach your students about how to find the area of a parallelogram (actually, it's technically a "rhomboid," because a parallelogram could also be a rectangle....) then you're most likely going to doing something bad like "multiply the base times the height," give a couple of dumb problems and call it a day.
That's NO way to teach geometry, more or less math, or anything for that matter!
This is a collection of geometric "dissections" where students cut out rhomboids, and, using a single, straight cut, convert it into a rectangle. There are "obvious" and "non obvious," as well as copious teaching tips AND 2 homework assignments that don't look like the cruddy ones that are in your textbooks or curriculum packets. For in these activities, students come to learn the following:
• ANY side of rhomboid can be the base, and the height has to be drawn in using a right angle from the base to the "top."
• Regardless of which side you decide is the base, the area will be the same.
• Every rhomboid can be turned into a rectangle using a single, straight cut. Even the ones that look "weird."
So do something fun and interesting with your students, teach them something important!
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