From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to demonstrate that a diagonal line drawn from one corner of a rectangle to another will generate two equivalent triangles.

**It’s Black Friday week on WonderHowTo!** Don’t miss out on all of the big sales in the Gadget Hacks and Null Byte shops. And if you’ve been wanting to take some classes without going into debt, check out our best deals on online courses for a variety of skill sets. Don’t miss out on these huge discounts:

**See Gadget Hacks’s top 10 BF sales on online courses (up to 99% off) >**

**See Null Byte’s top 13 BF sales on online courses (up to 99% off) >**

## Be the First to Comment

## Share Your Thoughts