# De utilitate mathematicae 38

Theon Smyrnaeus, De utilitate mathematicae, Paragraph 38. Ancient Greek.

Canonical: https://interlinea.aeterna-institute.org/library/greek/theon-smyrnaeus/de-utilitate-mathematicae/38

λέγονται δέ τινες καὶ κυκλοειδεῖς καὶ σφαιροειδεῖς καὶ ἀποκαταστατικοὶ ἀριθμοί· οὗτοι δʼ εἰσὶν οἵτινες ἐν τῷ πολλαπλασιάζεσθαι ἢ ἐπιπέδως ἢ στερεῶς, τουτ- έστι κατὰ δύο διαστάσεις ἢ κατὰ τρεῖς, ἀφʼ οὗ ἂν ἄρξωνται ἀριθμοῦ ἐπὶ τοῦτον ἀποκαθιστάμενοι. τοιοῦ- τον δέ ἐστι καὶ ὁ κύκλος· ἀφʼ οὗ ἂν ἄρξηται σημείου, ἐπὶ τοῦτο ἀποκαθίσταται· ὑπὸ γὰρ μιᾶς γραμμῆς περι- εχόμενος ἀπὸ τοῦ αὐτοῦ ἄρχεται καὶ εἰς ταὐτὸ καταλή- γει. τοιαύτη δὲ καὶ ἐν στερεῷ ἡ σφαῖρα· κύκλου γὰρ κατὰ πλευρὰν περιαγομένου ἡ ἀπὸ τοῦ αὐτοῦ ἐπὶ τὸ αὐτὸ ἀποκατάστασις σφαῖραν γράφει. καὶ ἀριθμοὶ δὴ οἱ ἐν τῷ πολλαπλασιασμῷ ἐφʼ ἑαυτοὺς καταλήγοντες κυκλικοί τε καλοῦνται καὶ σφαιροειδεῖς· ὧν εἰσιν ὅ τε ε΄ καὶ ὁ Ϛ΄· πεντάκις γὰρ ε΄ κε΄, πεντάκις κε΄ ρκε΄, ἑξά- κις Ϛ΄ λϚ΄, καὶ ἑξάκις λϛ΄ σιϚ΄.

---

Theon Smyrnaeus, De utilitate mathematicae, ed. Eduardus Hiller. Text: The Greek Library, from the Perseus Digital Library and other open sources, CC BY-SA 4.0. Changes: apostrophes normalised and the text divided into reading sections by Interlinea.
License: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/). Source: https://thegreeklibrary.pages.lisn.upsaclay.fr/works/tlg1724.tlg001.local001/.