How to Determine whether 2 triangles are similar in geometry

Looking for instructions on how to determine whether two triangles are similar in geometry? 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 (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to determine whether two triangles have the same proportions.