Often, I get students that will tell me that they pythagorean theorem is a^2+b^2=c^2, but won't have any idea what that means. This activity helps the students to see the relationships between the legs and the hypotenuse of a right triangle in an hand-on and engaging way. Even upper level students enjoy it!
Teachers will need copies of the handouts and some small object to use to cover the regions to compare areas. I find that a large bag of dried beans is inexpensive and easy to use. Plus, they can be kept for a long time and used over and over again.