It was Pythagoras' theorem regarding the properties of right angle triangles
Chat with our AI personalities
The Persians discovered the theory long before Pythagoras, but Pythagoras made it well known and proved it many times. He got the idea from the Egyptian rope-stretchers, of which you can ask another question for them.
the
Socrates was born after Pythagoras died.
Pythagoras dies before Archimedes was born.
Pythagoras died before Euclid was born.