For people who want to know more about how Eratosthenes and the Greeks estimated the size, within a few percent. https://en.wikipedia.org/wiki/Eratosthenes htt

For people who want to know more about how Eratosthenes and the Greeks estimated the size, within a few percent. https://en.wikipedia.org/wiki/Eratosthenes https://en.wikipedia.org/wiki/Eratosthenes