Eratosthenes (Geographer)

Eratosthenes was an ancient Greek scholar, geographer, and mathematician who lived around 276 to 194 BC. He is best known for calculating the Earth's circumference with remarkable accuracy using geometry and the angles of shadows cast by the sun in different locations. By measuring the shadow lengths in two cities, Alexandria and Syene, and knowing the distance between them, he estimated the Earth’s size to be about 40,000 kilometers. Eratosthenes is also credited with coining the term "geography" and creating one of the earliest maps of the known world, making significant contributions to our understanding of geography and mathematics.