A treatise on special or elementary geometry (1877)
Olney, Edward, 1827-1887, Olney, Edward, 1827-1887. Elements of trigonometry, plane and spherical · New York : Sheldon · leaf 245
is placed in itsequal AB, A at A, and B at B, C and C will fall onopposite sides of AB. We maj% however, construct ABC,Fig. 337, symmetrical with ABC in this figure, and ap-ply ABC oiFig. 338 to it, and find that they coincide.Now, ABC, Fig. 337, and ABC, Fig. 338, are equivalentFig. 338. {58:^);… … OF SPHERICAL TRIANGLES. 225 triedrals are formed, having the facial angle AOB = AOB , AOC = AOC,the included diedrals equal, and the parts similarly disposed, whence the trie-drals are equal. In like manner the triedral 0-ABC, Fe^r. 338, is symmetricaland equivalent to O-ABC, Fig. 338. Hence, in…
Geometry · Trigonometry
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