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Kids.net.au - Encyclopedia Eratosthenes - (482 words) |
 | Eratosthenes (276 BC - 194 BC) was a Greek mathematician, geographer and astronomer with (probably) Chaldean origins. |
| In 236 BC he was appointed by Ptolemy III Evergetes I as a head and the third librarian of the Alexandrian library. |
| He believed the Earth was a sphere and circa 240 BC he calculated its diameter, using trigonometry and information on the angle of the Sun at noon in Alexandria and Syene[?] (now Aswan, Egypt), whose distance from each other was known from caravan travellings to be 5,000 stadia. |
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