Visual Proof of the Pythagorean Theorem

Beautifully done!

[From Girl’s Angle: A Math Club for Girls, via Albany Area Math Circle.]

Do you know why this proof works? How can we be sure the red and yellow areas don’t change as they slide around?

Continue reading Visual Proof of the Pythagorean Theorem

Graph-It Game

[Photo by Scott Schram via Flickr.]

For Leon’s Christmas gift, Alex made the Graph-It game. She wrapped a pad of graph paper and wrote up the instructions:

To play Graph-It, one person designs a picture made by connecting points on a coordinate graph. He reads the points to the other player, who tries to reproduce the picture.

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Math Teachers at Play #33 via Old Math Dog

Photo by Moe via Flickr

The Math Teachers at Play blog carnival is open for your browsing pleasure at An “Old Math Dog” Learning New Tricks. Topics include:

  • humor
  • construction
  • baking
  • water gun battles
  • football
  • ABCs
  • puzzles, games, and much more… Enjoy!

Renée’s Platonic Mobile

Alexandria Jones struggled to think of a Christmas gift that a one-month-old baby could enjoy, but finally she got an idea.

She cut empty cereal boxes to make regular polygons: 6 squares, 12 regular pentagons, and 32 equilateral triangles. Using small pieces of masking tape, she carefully formed the five Platonic solids. Then she mixed flour and water into a runny paste. She tore an old newspaper into small strips and soaked them in the paste. She covered each solid with a thin layer of paper.

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Fun with Math Doodling

Thank you to Dan at Math 4 Love, who pointed me to Vi Hart’s math doodles. (The rest of her page is well worth exploring, too!) Kitten really enjoyed this one and immediately sat down to create her own version of the OuroBorromean Rings…

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