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 130
erefore AB:AC : : AC : CE. Wherefore to the twogiven straight lines AB, AC athird proportional, CE is found. Whichwas to be done. PROP. XII. PROB. To find a fourth proportional to three given straight lines. Let A, B, C be the three given straight lines; it is required to finda fourth proportional…
Euclid's Elements · Geometry · Trigonometry
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