The elements of Euclid for the use of schools and colleges; comprising the first six books and portions of the eleventh and twelfth books; (1903)
Euclid, Todhunter, I. (Isaac), 1820-1884, ed. edt, Simson, Robert, 1687-1768, ed. edt · London; New York, Macmillan · leaf 193
ties of the other two;and it will touch the straight lines BC, CA, AB, because theangles at the points D, E, F are right angles ; [IIL 16, Cor. 1..•. the circle DEF is inscribed in the triangle ABC. Wherefore a circle has been inscribed in the given triangle, [q.e.f. BOOK IV. 4.Additional… … CI i> Construction. Produce AB aud AC to G and H;bisect the exterior angles GBC, HCB by the straight lines BI^which meet at I^;draw IjD, I^E, and I^F perpendicular to BC, CA, and AB respectively. Proof. In the triangles IjBD, IiBF, r the zIiBD^the zIjBF, because ^ and the right Z I^DB = the…
Euclid's Elements · Geometry · Mathematics, Greek
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