Elements of geometry : containing the first six books of Euclid, with a supplement on the quadrature of the circle, and the geometry of solids : to which are added, Elements of plane and spherical geometry (1826)
Playfair, John, 1748-1819, Euclid · Philadelphia : Marot & Walter · leaf 312
of Euclid. This proposition, however, is subject to a restriction in certain ca-ses, which,! believe, was first observed by M. le Sage of Geneva, ina commnnieation to the Academy of Sciences of Paris in 1^56. Whenthe section of the pyramid formed by the planes that contain tlie so-lid angle is a… … NOTES. SUPPL. BOOK II. 311 like that which is annexed, viz.ABCD, having some angles, suchas 3DC, exterior, or, as they aresometime!! caned,reeutering angles,the pri»position is not necessarilytrue; and it is plain, that in suclicases the demonstration which wehave given, and which is the samewiih…
Euclid's Elements · Geometry · Trigonometry
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![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-66-43.webp)
