Noun
(mathematics) the trigonometry of spherical triangles
Source: WordNetSpherical trigonometry and certain other theorems, to which the author has added a new one of frequent application, then serve for the solution of the problems which the comparison of the various directions involved can present. Carl Friedrich Gauss
Based on this definition, the galactic poles and equator can be found from spherical trigonometry and can be precessed to other epochs ; see the table. Source: Internet
He might have used spherical trigonometry. Source: Internet
Thus spherical trigonometry differs from ordinary trigonometry in many respects. Source: Internet