A simple geometry demonstration using crackers

Props used for demonstrations don’t have to be complicated or expensive to be effective. As is shown above, the Pythagorean theorem say that, for a right triangle, the square of the hypotenuse (c ) is equal to the sum of the squares of the other two sides (a and b).

In Bobby Mercer’s new book, Junk Drawer Geometry: 50 awesome activities that don’t cost a thing, he has a clever demonstration of it on page 60 using fifty square cheese crackers. (You can read it on Google Books). As shown above, this example is for a = 3, b = 4, and c = 5.  I used 1” square Kellogg’s Reduced Fat Cheez Its. Of course, you could instead use larger crackers like Saltines.

Junk Drawer Geometry was preceded by two other books by Mr. Mercer with the exact same subtitle on the topics of Physics (2014) and Chemistry (2016).

When you look on YouTube for demonstrations of that theorem you can find another version using square Starburst candies, one with 4.5 mm diameter bearing balls, and several using water in connected flat containers. In The Wizard of Oz the scarecrow incorrectly states the theorem as being for an isosceles triangle. So does Homer Simpson, but he gets corrected immediately.

An image illustrating the theorem was adapted from one at Wikimedia Commons.