Who is the origin of right angle, acute angle and obtuse angle?

The source can't be traced back, but the name has a source: 1, obtuse angle: "Cutting the meat with a blunt knife-the more you cut it, the more it hurts". The ancients found that this angle was very similar to the shape of a "blunt knife", so it was called an "obtuse angle". 2. Right angle: In ancient times, when the magic fairy was building a house, it was required to be perpendicular to the ground. This angle was called "vertical angle" in life.