Most trigonometry students look at triangles on a flat surface. However, people from ancient astronomers to modern navigators calculated the arc lengths and angles of triangles on a sphere. They used ...

THE author of this book, who is one of the naval instructors on H.M.S. Britannia, has brought together the most important rules which are used in the solution of spherical triangles, and, after ...

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IN modern treatises on crystallography, the crystal is imagined projected radially on the surface of a sphere, and the spherical triangles so obtained are dealt with by spherical trigonometry.