This Photo Disproves The One Thing That Everybody Knows About Triangles

Everyone learns the number one rule about triangles in high school: the angles of a triangle add up to 180 degrees.But did you know that sometimes they don't? Triangles are much more interesting than you ever imagined. We're going to disprove this fact with one picture.Keep in mind, however, that the above rule (namely, that the angles of a triangle add up to 180 degrees) is not false. In fact, it is true — however, it is only true in Euclidean geometry. That's the geometry that you learned in...