WORLD CIVILIZATION

Detailed explanation-1: -In the third century BCE, Eratosthenes, a Greek librarian in Alexandria, Egypt, determined the earth’s circumference to be 40, 250 to 45, 900 kilometers (25, 000 to 28, 500 miles) by comparing the Sun’s relative position at two different locations on the earth’s surface.

Detailed explanation-2: -Eratosthenes may have been the first to use the word geography. He invented a system of longitude and latitude and made a map of the known world. He also designed a system for finding prime numbers-whole numbers that can only be divided by themselves or by the number 1.

Detailed explanation-3: -Eratosthenes of Cyrene (/ɛrəˈtɒsəniːz/; Greek: [eratostʰénɛːs]; c. 276 BC – c. 195/194 BC) was a Greek polymath: a mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria.