SSC MTS EXAM

Detailed explanation-1: -Eratosthenes hired a man to pace the distance between the two cities and learned they were 5, 000 stadia apart, which is about 800 kilometers. He could then use simple proportions to find the Earth’s circumference-7.2 degrees is 1/50 of 360 degrees, so 800 times 50 equals 40, 000 kilometers.

Detailed explanation-2: -Eratosthenes method was very simple; he measured the length of a shadow from a vertical stick of a known height in two cities on the same day. The ratio between the north-south distance between the two cities and the angles measured gave a ratio which allowed Eratosthenes to calculate the size of the Earth.

Detailed explanation-3: -He determined that Alexandria is about 5, 000 stadia (489 miles) North of Syene. Given these estimations, Eratosthenes was able to calculate the circumference of the Earth to be 250, 000 stadia. The length of one stadia is not exactly known, but it is thought to be between 515 and 686 feet.