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 74
le EBA is equal to the an-gle EDF; but EDF is a right angle, wherefore EBA is a right angle;and EB is drawn from the centre: but a straight line drawn fromthe extremity of a diameter, at right angles to it, touches the circle(Cor. 16. 3.) : Therefore AB touches the circle; and is drawn fromthe… … 7* ELEMENTS PROP. XVIII. THEOR. If a straight line touch a circle, the straight line drawnfrom the centre to the point of contact, is perpendicularto the line touching the circle. Let the straight line DE touch the circle ABC in the point C;take the centre F, and draw the straight line EC : FC is…
Euclid's Elements · Geometry · Trigonometry
Internet Archive · Public Domain Mark 1.0. Free to use for anything.
![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-338-229.webp)
