The elements of Euclid : viz, the first six books, together with the eleventh and twelfth : the errors, by which Theon, or others, have long ago vitiated these books, are corrected, and some of Euclid's demonstrations are restored : also, The book of Euclid's data, in like manner corrected (1834)
Euclid, Euclid, Simson, Robert, 1687-1768 · Philadelphia : Desilver & Thomas · leaf 71
gle BEC isdouble of the angle BAC. First, let E the centre of the circle bewithin the angle BAC, and join AE, andproduce it to F; because EA is equal toEB, the angle EAB is equal (5. 1.) to theangle EBA; therefore the angles EAB,EBA are double of the angle EAB, but theangle BEF is equal (32. 1.) to… … See Note. BOOK III. THE ELEMENTS OF EUCLID. (i9 Again; let E the centre of the circlebe without the angle BDC, and join DEand produce it to G. It may be demon-strated, as in the first case, that the angleGEC is double of the angle GDC, andthat GEB a part of the first is double ofGDB a part of the…
Mathematics, Greek · Geometry · Trigonometry
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