The first six books of the elements of Euclid, in which coloured diagrams and symbols are used instead of letters for the greater ease of learners (1847)
Byrne, Oliver, Whittingham, Charles, 1795-1876, Chiswick Press · London : William Pickering · leaf 101
+ by ^ + 2 • + By pr. 4, B. 2. ^ + > + 2 add ——— ^ to both 2 _ V (pr. 47, B. I.) + + • or ■; hence by 2 ^ (pr. 47, B. I.). Therefore, ^ • -■ + + Q. E. D. 68 BOOK II. PROP. XIII. THEOR. FIRST. SECOND. … ^m F^ p^ Br^/^ ^ N any tri-angle, thefquareoftheJidefubtend-ing an acute angle, islefs than the fum of thefquares of the Jides con-taining that angle, by twice the reSlangle contained by eitherof thefe fides, and the part of it intercepted between the foot ofthe perpendicular let fall on it from…
Euclid's Elements · Geometry
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