3. Ad prop. XXVII. Ἄλλως.
φέρεια γεγράφθω ἡ ΓΒΔ· θέσει ἄρα ἐστὶν ἡ ΓΒΔ. θέσει δὲ καὶ ἡ ΑΒ εὐθεῖα· δοθὲν ἄρα ἐστὶ τὸ Β σημεῖον.
Data (demonstrationes alterae). Euclid. ed. Johan Ludvig Heiberg, ed. Heinrich Menge. United States. 2016.
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