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 160
, AF will bo containeda certain number of times, eiaetly^ in the arch AB, aud thertfore itwill also be contained a certain number of times, exactly, in the wholecircumference, ABC; and the straight line AF is therefore the side ofan equilateral polyy^on inscribed inthe circle ABC. Wherefore also,HL… … Ijecause these polygons are similar (Cor. 3.1.), they are as the squaresof the homologous sides, HL and AF (Sup. 3. Cor. 30. 6.), that is, be-cause the triangles HLG, AFG are similar, as the square of HG tothe square of x\G,that is of GK. But the triangles HGK, ACF havebeen proved to be similar,…
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-356-247.webp)
