## Using Geogebra to Geometrically Prove Pythagorean Theorem

*February 23, 2012 at 9:45 pm* *
1 comment *

Hi all,

Below is the common geometric proof of pythagorean theorem. The idea is that since the sum of the areas of the triangles doesn’t change between these two squares, the total of the hatched areas does as well. Therefore The area of the square on the left – who’s side is represented by the hypotenuse of the 4 identical right triangles – must be the same as the area of the little square on the right (who’s one side is “a” units) plus the larger square on the right (who’s area is b units). In other words a^2+b^2=c^2.

The tutorial below shows how to create the diagram above using geogebra as an interactive simulation (changing the sliders changes the shape of the triangles, yet the property always stays the same):

The recording cut out at the end, but the only things I did after that part were purely asthetic.

Cheers,

Doug

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1.Michelle | August 31, 2012 at 12:42 amI love the small and easy process you went through to prove something so commonly known. I continue to be amazed at the power of GeoGebra and learned at least 3 new things from your video about GeoGebra. Thanks!!