The first six books of the elements of Euclid, in which coloured diagrams and symbols are used instead of letters for the greater ease of learners (1847)
Byrne, Oliver, Whittingham, Charles, 1795-1876, Chiswick Press · London : William Pickering · leaf 108
STRAIGHT line C—)joining two points in thecircumference of a circle lies ivholly within the circle. Find the centre of o (B.S-pr.i.); … from the centre draw to any point in meeting the circumference from the centre ;draw ——— and . Then = -^ (B. i.pr. 5.) but or CZ ^ (B. I. pr. 16.) (B. I. pr. 19.) but .*. every point in lies within the circle.Q. E. D. 76 BOOK III. PROP. III. THEOR.
Euclid's Elements · Geometry
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