SCHOLIA.

127. Ὥστε καὶ τοῦ ὑπὸ τῶν ΓΒ∠ p. 120, 13] καί ἐστιν ὡς ἡ Β∠ πρὸς ∠Α, οὕτως τὸ ὑπὸ ΓΒ, ∠Β πρὸς τὸ ὑπὸ ΓΒ, Α∠. 128. Πόθεν, ὅτι ἐστὶν ὡς ἡ Β∠ πρὸς ∠Α, οὕτως καὶ τὸ ὑπὸ τῶν ∠Β, Β∠ πρὸς τὸ ὑπὸ τῶν ΒΓ. Α∠; ἐκκείσθω τις εὐθεῖα ἡ εζ καὶ ἀφῃρήσθω ἀπʼ αὐτῆς τῇ μὲν Β∠ ἴση ἡ εδ, τῇ δὲ ∠Α ἴση ἡ δζ, καὶ πρὸς ὀρθὰς ἡ ηδ ἴση οὗσα τῇ ΒΓ. ἐπεὶ οὖν ἐστιν ὡς ἡ εδ πρὸς δζ, οὕτως τὸ εη πρὸς ηζ, καί ἐστι τὸ μὲν εη τὸ ὑπὸ τῶν εδ, δη, τουτέστι τὸ ὑπὸ τῶν Β∠, ΒΓ, τὸ δὲ ηζ τὸ ὑπὸ τῶν ζδ, δη, τουτέστι τὸ ὑπὸ τῶν ΒΓ ∠Α· ἴση γὰρ ἡ μὲν δη τῇ ΒΓ, ἡ δὲ δζ τῇ ∠Α· λόγος ἄρα ἐστὶ καὶ τὰ ἑξῆς. 129. Καί ἐστι τὸ δὶς ὑπὸ των ΓΒ, Β∠ p. 120,17–18] ὡς ἐν τῷ β΄ τῶν στοιχείων ἐν τῷ ιγ΄ θεωρήματι ἐν τοῖς ὀξυγωνίοις τριγώνοις.