Elements of geometry : containing the first six books of Euclid, with a supplement on the quadrature of the circle, and the geometry of solids : to which are added, Elements of plane and spherical geometry (1826)
Playfair, John, 1748-1819, Euclid · Philadelphia : Marot & Walter · leaf 93
93 ELEMENTS … will meet one another: for, if they do not meet, they are parallel,wherefore, AB, AC, which are a^ri2;ht angles to them, are parallel,which is absurd: Let them meet in F, and join FA ; also, if the pointF be not in BC, join BF, CF: then, because AD is equal to DB, andDF common, and at right angles…
Euclid's Elements · Geometry · Trigonometry
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