Sure, Eratosthenes got it more accurately than Aristotle did, but Aristotle was only 5000 miles out, came before Eratosthenes (died about 50 years before Eratos

Sure, Eratosthenes got it more accurately than Aristotle did, but Aristotle was only 5000 miles out, came before Eratosthenes (died about 50 years before Eratosthenes was born) and on the scale of a planet, with the technology he had available, I'd say thats reasonably good