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 69
OOK 1. 32. 67 Proposition 32. Theorem. // a side of any triangle he produced,(1) the exterior angle is equal to the two interior and opposite angles;and (2) the three interior angles of the triangle are together equalto two right angles. Let ABC be a triangle, and let one of its sides BC be… … Construction. Through the point C draw CE parallel toAB. [1.31. Proof. (1) Because AB is parallel to CE, and AC meetsthem, the alternate angles BAC, ACE are equal. [I. 29. Again, because AB is parallel to CE, and BD meets them,the exterior angle ECD is equal to the interior and oppositeangle ABC.…
Euclid's Elements · Geometry · Mathematics, Greek
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