- On the geoboard or dot paper:
- Geometry Labs, 8.4 to 9.4 — a whole unit: an exploration of the areas of tilted squares leads to the Pythagorean theorem and to a better understanding of radicals.
- A philosophical discussion of the above.
On grid paper — breaking down a proof into images, step by step.
- Online:
- Puzzle — arrange the pieces to show `a^2+b^2`, then rearrange to show `c^2`.
- Animation 1
- Animation 2
- Animation 3
- For maximum impact, only show the animations after having done some of the preceding work.
- Guided inquiry: The Three Triangles, a proof of the theorem based on similar triangles.
- Teacher Notes