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 82
ne equal side of eachcoincident, and the other two equal sides in the same straight line.Then apply Ex. L] ##4. Prove that the four triangles into which a parallelogram isdivided by its diagonals are equal in area. [Use Ex. 4, page 64.] 70 EUCLIDS ELEMENTS. Proposition 39. Theorem. Equal triangles… … Construction. Join AD.AD shall be parallel to BC. For if it is not, let AE be parallel to BC, and let it meetBD at E, [I. 31. and join EC. Proof. The A ABC = the A^BC, because they are on thesame base BC, and between the same parallels BC, AE. [L 37.But the A ABC = the A DBC ; {Hypothesis. .-. also…
Euclid's Elements · Geometry · Mathematics, Greek
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