Ball, W. W. Rouse (Walter William Rouse), 1850-1925 · London, Macmillan · leaf 69
ects DA and is perpendicular to it, wehave the angle ODA equal to the angle OAD, Hence the angle ADO (which is the difference of ODO andODA) is equal to the angle DJ.-^ (which is the difference ofOAE and OAD). But ADO is a right angle, and DAE isnecessarily greater than a right angle. Thus the… … acute, and that the angle A is greater than the angle 0. FromA draw AD making the angle BAD equal to the angle (7, andcutting BO in D. From A draw AE perpendicular to BO. The triangles ABO, ABD are equiangular; hence, by Euc.VI. 19, A ABO : AABD=AO^ : AD\ Also the triangles ABO, ABD are of equal…
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