The elements of Euclid : viz, the first six books, together with the eleventh and twelfth : the errors, by which Theon, or others, have long ago vitiated these books, are corrected, and some of Euclid's demonstrations are restored : also, The book of Euclid's data, in like manner corrected (1834)
Euclid, Euclid, Simson, Robert, 1687-1768 · Philadelphia : Desilver & Thomas · leaf 83
any point without a circle two straight huesbe drawn, one of which cuts the circle, and the othertouches it; the rectangle contained by the whole linewhich cuts the circle, and the part of it without thecircle, shall be equal to the square of the line Avhichtouches it. Let D be any point without… … Either DCA passes through the centre, or it does not; first, letit pass through the centre E, and join EB; therefore the angleEBD is a right (18. 3.) angle: and becausethe straight line AC is bisected in E, andproduced to the point D, the rectangle AD,DC, together with the square of EC, isequal (6.…
Mathematics, Greek · Geometry · Trigonometry
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