Who discovered the size of earth?

1 Answer

Eratosthenes a greek librarian found the circumference of earth around 280BC. .

Explanation:

He found image the sun in a well at mid day.and another place 8oo kilometers away a vertical stick was giving a shadow of 7 degree.. So if 800 Km is 7 degree 360 degree will be around 400,000 kilometers. The places were Alexandria and Aswan in Egypt.