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 247
^circle passing through B and Then because E is thepole of the circle ACD, ECis a (3.) quadrant, and theplane of the circle EC (4.)is at right angles to the planeof the circle ACD, that is,the spherical angle ACE is a ,right angle; and therefore,when AB is less than AE,the angle ACB, being lessthan… … SPHERICAL TRIGONOMETRY. s^V PROP. XV. If the two sides of a right angled spherical triangle aboutthe right angle be of the same affection, the hypotenusewill be less than a quadrant; and if they be of different af-fection, the hypotenuse will be greater than a quadrant. Let ABC be a right angled…
Euclid's Elements · Geometry · Trigonometry
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