Proofs Without Words
These visual examples of geometry ideas are sometimes called Proof Without Words.
- Try this one. It shows a conclusion about the sum of the three interior angles of any triangle by folding down the corners of the triangle. Ingenious!
- Next, try this one. It shows the same conclusion about the sum of the three interior angles of any triangle in a different way. Grab a vertex, move it around, and watch what happens.
- How about the sum of the exterior angles of a polygon? Go here. This is an amazing way to show a powerful conclusion in geometry. If you wish add a side to the polygon by using a Command click on a Mac. Beautiful!
- How about a proof for the Quadrilateral? Or Pentagon? Or even a Hexagon? Go here. (You may want to scroll down the page some).
Look at the visual proof of the Pythagorean Theorem using a dissection method.
One more proof of the Pythagorean theorem, this time using WATER!
One more proof of the Pythagorean theorem, this time using WATER!
Area of a Rectangle (animated)
Area of a Parallelogram (animated)
Area of a Triangle (animated)
Area of a Trapezoid (animated)
Area of a Circle (animated)
Area of a Parallelogram (animated)
Area of a Triangle (animated)
Area of a Trapezoid (animated)
Area of a Circle (animated)