The elements of Euclid for the use of schools and colleges; comprising the first six books and portions of the eleventh and twelfth books; (1903)
Euclid, Todhunter, I. (Isaac), 1820-1884, ed. edt, Simson, Robert, 1687-1768, ed. edt · London; New York, Macmillan · leaf 323
x angles CBA, BCA, ACD, CD A, ADB,ABD are greater than two right angles ;.-. the remaining three angles BAC, CAD, DAB, which con-tain the solid angle at A, are together < four right l\ (ii.) Let the solid angle at A be contained by any numberof plane angles BAC, CAD, DAE, EAF, FAB:these shall be… … Proof. Because the solid angle at B is contained by thethree plane angles CBA, ABF, FBC;.-. the angles CBA, ABF are together > the Z.FBC. [XI. 20. Similarly, at each of the points C, D, E, F, the two planeangles which are at the bases of the triangles having thecommon vertex A, are together >…
Euclid's Elements · Geometry · Mathematics, Greek
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