Then, since the two sides DC, CE are equal to the two sides FA, AG respectively, and the base DE is equal to the base FG, the angle DCE is equal to the angle FAG. [I. 8]
Quoniam enim duo latera C I, C K, æqualia sunt duobus lateribus E G, E H, utrumque utrique, & basis I K, basi G H, per constructionem; erit angulus C, angulo E, æqualis: