The Proof of the Century!

Print this page and distribute to students.

Follow the directions below to complete one proof of the Pythagorean theorem.

1. You will need two copies of Student Organizer #3: Pythagorean Theorem Diagram.

2. Using one of the copies, cut out square (1).

3. Cut out square (2) and then cut along the dotted lines so you are left with 4 pieces.

4. Using the second copy of the diagram, notice that the middle of square (3) is identical to square (1). Tape or glue square (1) over the center in square (3). Take the pieces from square (2) and fit them around the center of square (3).

5. You have just proven the Pythagorean theorem!

Take a look at United States Naval Academy Mathematics Department (http://www.nadn.navy.mil/MathDept/mdm/pyth.html) to see a similar approach.

6. Can you form an algebraic argument for why this proof works?