What is the approximate circumference of earth ........

Explanation:

Well, we believe that the unit of the "stadium" was about 0.15 km. This means that Eratosthenes estimated the circumference of the Earth to be about 40,000 km. Earth's circumference is the distance around the Earth; around the poles it measures almost exactly 40,000 kilometres or 21,600 nautical miles due to the circumference being used to define those units of measurement.