Roelof Berkepeis's video: Flat Earth Proof

Part of the presentation "Flat Earth for DUMMIES" by Rob Skiba, see https://www.youtube.com/watch?v=osBuCleQfdo He says "a 90 degree triangle", but this is nonsense, such thing does not exist; as everybody should know, the 3 angles of every triangle add up to 180 degrees. What DOES exist is the so called "right triangle", which has one 90 degree angle and two acute angles. When going 10.000 km in one direction on the earth surface, then turn 90 degrees and go another 10.000 km, then again turn 90 degrees and go another 10.000 km, you would return to the place you started, as shown in the video. The 10.000 km distance he mentions, is due to the size of our planet. This will indeed prove the earth is a globe, however doing so in practice will be an adventure ! Drawing a circle inside a triangle has no relation to anything ..