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 58
e done. PROP. XII. THEOR. In obtuse angled triangles, if a perpendicular be drawnfrom any of the acute angles to the opposite side pro-duced, the square of the side subtending the obtuse angleis greater than the squares of the sides containing the ob-tuse angle, by twice the rectangle contained by… … 38 ELEMENTS
Euclid's Elements · Geometry · Trigonometry
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