Strogatz applied the “Page 99 Test” to The Joy of x and reported the following:
Page 99 of The Joy of x gently explains the proof that the angles of any triangle always add up to 180 degrees. What I love about it -- and what makes it so representative of the book as a whole -- is that this proof showcases a side of math that most of us never encountered in school. As I write on the next page,Learn more about the book and author at Steven Strogatz's website.This is one of the most bracing arguments in all of mathematics. It opens with a bolt of lightning, the construction of the parallel line. Once that line has been drawn, the proof practically rises off the table and walks by itself, like Dr. Frankenstein’s creation.
And who knows? If we highlight this other side of geometry—its playful, intuitive side, where a spark of imagination can be quickly fanned into a proof—maybe someday all students will remember geometry as the class where they learned to be logical and creative.
Writers Read: Steven Strogatz (August 2009).
Writers Read: Steven Strogatz (November 2012).