# Scholia in opticorum recensionem Theonis (scholia vetera) 56

Scholia in Euclidem, Scholia in opticorum recensionem Theonis (scholia vetera), Section 56. Ancient Greek.

Canonical: https://interlinea.aeterna-institute.org/library/greek/scholia-in-euclidem/scholia-in-opticorum-recensionem-theonis-scholia-vetera/56

56. Ἴσὸν δὲ τὸ μὲν πρὸς τῷ Ν κτλ. p. 198, ἐὰν γάρ, καθὼς εἴρηται ἐν τῷ λαʹ θεωρήματι, ἀπὸ τοῦ Ν ὄμματος προσπέσωσιν ἀκτῖνες πρὸς τὴν τοῦ κώνου περιφέρειαν ὡς αἱ ΝΤ, ΝΦ, καὶ ἀπὸ τῶν Τ, Φ ἐπὶ τὴν κορυφὴν τὴν ∠ ἐπιζευχθῶσιν εὐθεῖαι ὡς αἱ Τ∠, Φ∠, τὸ διὰ τῶν ΝΤ, Τ∠ ἐπίπεδον καὶ τὸ διὰ τῶν ΝΦ, Φ∠ κοινὴν τομὴν ἕξει τὴν ∠Ν, ἐφʼ ἧς ἐὰν τεθῇ τὸ ὄμμα ὡς κατὰ τὸ Ν καὶ τὸ Θ, ἴσον ἀεὶ τοῦ κώνου τὸ ὁρώμενον ὀφθήσεται διὰ τὸ λαʹ θεώρημα· ὁμοίως καὶ ἐπὶ τῆς ΛΣ. Ad prop. XXXV.

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Scholia in Euclidem, Scholia in opticorum recensionem Theonis (scholia vetera), ed. Johan Ludvig Heiberg, H. Menge. 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/tlg5022.tlg004.local001/.