The first six books of the Elements of Euclid, in which coloured diagrams and symbols are used instead of letters .. (1847)
Euclid, Byrne, Oliver · London, W. Pickering · leaf 99
N any obtufe angledtriangle, thefquareof the fide fubtend-ing the obtufe angleexceeds the fum of the fquaresof the fides containing the ob-tufe angle, by twice the rec-tangle contained by either ofthefe fides and the producedpartsof the fame from the obtufeangle to the perpendicular letfall on it… … + * by By pr. 4, B. 2. -„..* = 2 _j 3 _|_ 2 „ . add -^—— 2 to both 2 + 2 = 8 (pr.47fB.i.) 2 • + + ■ or + (pr. 47, B. 1.). Therefore, » = 2 • ■ ~ : hence ■by 2 +- + + Q. E. D. 68 BOOK II. PROP. XIII. THEOR. FIRST SECOND.
Geometry
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