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 258
sides, tothe tangent of half the difference of the angles which theperpendicular makes with the same sides, when it fallswithin, or to the tangent of half the sum of these angles,when it falls without the triaugle. If ABC be a spherical triangle, and ADaperpendiculartothebaseBC, i^in. (C + B) :…
Euclid's Elements · Geometry · Trigonometry
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