The Pythagorean Theorem is one of the most interesting theorems for two reasons: First, it’s very elementary; even high school students know it by heart. Second, it has hundreds of proofs. The proof below uses triangle similarity.
Pythagorean Theorem
In a right triangle with side lengths 
A one-minute explanation that not all infinities are equal. The video shows that the number of real numbers from 0 to 1 is greater than the number of all natural numbers 1, 2, 3, 4, and so on.
If the video is too fast or too short, you can read a more detailed explanation in Counting the Real Numbers.
Posted in Set Theory
Tagged counting numbers, counting the real numbers, infinities, infinity, real numbers
The Math Teachers at Play Carnival 50 is now live at Mathematics for Teaching. Due to busyness, the Math and Multimedia Blog Carnival will have a break this month — unless someone volunteers to host it before the end of the month.
I have updated the following GeoGebra Tutorials to version 4.0: Spreadsheet, Slider, and Curves of Best Fit (Tutorial 20) ; and Spreadsheet and Similarity (Tutorial 21); Spreadsheet, Vectors and Matrices (Tutorial 22). Continue reading
Posted in Miscellaneous
Tagged GeoGebra 4.0 tutorials, math blog carnival, math teachers at play
Math Palette GeoGebra Central School of Freebies Blogineering
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