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 133
F a Jlraight line mmKmmmm^mbe a tangent to a circle,the Jlraight line », drawn perpendicular to it from point of the contact, pajfes through the centre of the circle. For, if it be poifible, let the centre be without and draw ■ ••■ from the fuppofed centreto the point of contact. Becaufe … (B. 3. pr. 18.) = 1 1, a right angle; but ^^ = I 1 (hyp.), and ,\ = a part equal to the whole, which is abfurd. Therefore the arTumed point is not the centre; and inthe fame manner it can be demonftrated, that no otherpoint without m^mm^m is the centre. Q. E. D. 102 BOOK III. PROP. XX. THEOR.…
Geometry
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