Eratosthenes of Cyrene (; Greek: Eratosthenes o Kurenaios, IPA:
Achievements
Eratosthenes was described by the Suda Lexicon as a Pentathlos (Pentathlos) which can be translated as "All-Rounder", for he was skilled in a variety of things: He was a true polymath. He was nicknamed Beta because he was great at many things and tried to get his hands on every bit of information but never achieved the highest rank in anything; Strabo accounts Eratosthenes as a mathematician among geographers and a geographer among mathematicians.  Eusebius of Caesarea in his Preparatio Evangelica includes a brief chapter of three sentences on celestial distances (Book XV, Chapter 53). He states simply that Eratosthenes found the distance to the Sun to be "stadion muriadas tetrakosias kai oktokismurias" (literally "of stadia myriads 400 and 80,000") and the distance to the Moon to be 780,000 stadia. The expression for the distance to the Sun has been translated either as 4,080,000 stadia (1903 translation by E. H. Gifford), or as 804,000,000 stadia (edition of Edouard des Places, dated 1974-1991). The meaning depends on whether Eusebius meant 400 myriad plus 80,000 or "400 and 80,000" myriad. With a stade of 185 m, 804,000,000 stadia is 149,000,000 km, approximately the distance from the Earth to the Sun.  Eratosthenes also calculated the Sun's diameter. According to Macrobious, Eratosthenes made the diameter of the Sun to be about 27 times that of the Earth. The actual figure is approximately 109 times.  During his time at the Library of Alexandria, Eratosthenes devised a calendar using his predictions about the ecliptic of the Earth. He calculated that there are 365 days in a year and that every fourth year there would be 366 days.  He was also very proud of his solution for Doubling the Cube. His motivation was that he wanted to produce catapults. Eratosthenes constructed a mechanical line drawing device to calculate the cube, called the mesolabio. He dedicated his solution to King Ptolemy, presenting a model in bronze with it a letter and an epigram. Archimedes was Eratosthenes' friend and he, too, worked on the war instrument with mathematics. Archimedes dedicated his book The Method to Eratosthenes, knowing his love for learning and mathematics.

Q: What was Eratosthenes greatest achievement?
A: Eratosthenes also calculated the Sun's diameter. According to Macrobious, Eratosthenes made the diameter of the Sun to be about 27 times that of the Earth.

Q: Did he think the sun revolves around the Earth?
A: The actual figure is approximately 109 times.

Q: Did he map the moon?
A: the distance to the Moon to be 780,000 stadia.

Q: Did he teach other Greek Philosophers?
A: During his time at the Library of Alexandria, Eratosthenes devised a calendar using his predictions about the ecliptic of the Earth.

Q: What else about the Library of Alexandria?
A: He calculated that there are 365 days in a year and that every fourth year there would be 366 days.

Q: What else had Eratosthenes discovered?
A: He was also very proud of his solution for Doubling the Cube.

Q: Are his discovers still used today?
A: He calculated that there are 365 days in a year and that every fourth year there would be 366 days.

Q: Has any of his works been lost over the years?
A: unknown
Does the article mention where he lived?
Eusebius of Caesarea
Eusebius of Caesarea