Wikidata facts
- Instance of
- human
- Gender
- male
- Citizenship
- Classical Athens
- Place of birth
- Athens
- Place of death
- Athens
- Occupation
- philosopher
- Languages spoken
- Ancient Greek
- Student of
- Theodoros of Cyrene
- Field of work
- mathematics
Show 6 more facts
- maintained by WikiProject
- WikiProject Mathematics
- date of birth
- 0417-00-00
- name in native language
- Θεαίτητος
- date of death
- 0369-01-01
- time period
- classical antiquity
- described by source
- Pauly–Wissowa
Sources (1)
via Wikidata · CC0
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Encyclopedic overview
Theaetetus of Athens (/ˌθiːɪˈtiːtəs/; Ancient Greek: Θεαίτητος, romanized: Theaítētos; c. 417 – c. 369 BCE), possibly the son of Euphronius of the Athenian deme Sunium, was a Greek mathematician. His principal contributions were on irrational lengths, which was included in Book X of Euclid's Elements and proving that there are precisely five regular convex polyhedra. A friend of Socrates and Plato, he is the central character in Plato's eponymous Socratic dialogue.
Theaetetus, like Plato, was a student of the Greek mathematician Theodorus of Cyrene. Cyrene was a prosperous Greek colony on the coast of North Africa, in what is now Libya, on the eastern end of the Gulf of Sidra. Theodorus had explored the theory of incommensurable quantities, and Theaetetus continued those studies with great enthusiasm; specifically, he classified various forms of irrational numbers according to the way they are expressed as square roots. This theory is presented in great detail in Book X of Euclid's Elements.
Excerpted from Wikipedia’s “Theaetetus” article, available under the CC BY-SA 4.0 licence.