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 261
O find a third proportionalto two given Jiraight lines At either extremity of the givenline -^^—^ draw ..-—making an angle ; take......... r= , and draw ■ ; make ........ ~ and draw ........ (B. 1. pr. 31.) .■uj-jj is the third proportional to ——— and . … For fince ...■a n..i..« (B. 6pr. 2); but — ■(conft.); (B. 5. pr. 7). Q^E. D. 230 BOOK VI. PROP. XII. PROB.
Geometry
Internet Archive · Thomas Fisher Rare Book Library · Public Domain Mark 1.0. Free to use for anything.
