Eratosthenese


 * ==**Eratosthenes was born 276 b.c. and died in 194 b.c. He was born in Cyrene which is present day Libya in Northern Africa[[image:http://www.crystalinks.com/eratosthenes.png align="left" caption="Eratosthenese greek Mathematician"]].**==


 * ==Eratosthenes figured that Cyrene to Alexandria is 500 miles from each other in distance. That was about 1/50th of the earths circumference, so the whole earths is 250,000 miles in circumference.==
 * ==Eratosthenes was famous for his work with prime #'s, and measuring the diameter of the earth. he also made a calender with leap years, and a 675 star catalog( now lost), and maps.==
 * ==in Eratosthenes later years he became blind,he thought being blind wouldn't help him in any way so by the age of 80 he committing suicide by starvation.==
 * ==He measured the tilt of the earths axis by 23.5 degrees, today that gives us the 4 seasons.==
 * ==Eratosthenes was invited by Ptolemy to come to Alexandria and teach his son at the famous library in Alexandria.==