Interesting Facts. Episode 2. Triangle on a Sphere
The normal triangle, on a flat surface, has 180 degrees of angles. Basically, if you add up all the values of the angles in a triangle, you will get 180 degrees. That is, if the triangle is on a flat surface.
Imagine that you have the globe in your hands. You position a pencil on the North pole, then go down the Greenwich meridian to the Equator and turn 90 degrees to the right along the equator to the Indian Ocean (right under India itself), then turn 90 degrees left again and go up, up, up… where will we find ourselves? That's right, at the North Pole again. We turned 90 degrees three times, bringing our total of turns to 270 degrees, and we made a perfect triangle on a sphere. So if you add up the angles in a triangle on a sphere, you will get not 180, but 270 degrees.
Can you believe that?