27. Καὶ ἀμβλεῖά ἐστιν p. 318, 11 ἐπειδὴ ἡ ἀπὸ τοῦ
 κέντρου ἐπὶ τὴν ἁφὴν ἐπιζευγνυμένη ὀρθὴν ποιεῖ τὴν ὑπὸ ΘΑΚ, ὀξεῖα ἄρα ἡ ὑπὸ
 ΘΚ Α ἀμβλεῖα ἄρα ἡ ὑπὸ ΑΚΕ.