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Definition 11

Similar segments of circles are those which admit equal angles, or in which the angles equal one another.

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Since the segments BGC and EHF have in them equal angles BGC and EHF, this definition declares them to be similar segments.

This is hardly a proper definition considering that proposition III.21 has yet to be proved in which it is shown that all the angles in one segment are equal.

Book III Introduction - Definition III.10 - Proposition III.1.

© 1996
D.E.Joyce
Clark University