New plane and spherical trigonometry, surveying, and navigation (1903)
Wentworth, G. A. (George Albert), 1835-1906 · Boston : Ginn & Company · leaf 56
5280 sin 5° a5280*5280 sin 5°. .-. a = log 5280 = 3.72263log sin 5° = 8.94030- 10 log a = 2.66sin 10° : a loga = colog sin 10° = log c = cos 75° = .-.6 =log c = sin 10°2.662930.760333.42326 b c c cos 75°. 3.42326 9.41300 - 10 log cos 75° log b = 2.83626 6 = 685.9Height of hill is 685.9 feet. 64. A… … Let B represent the fort, AC thehorizontal plain, BC a ± from fortto plain. BA C = angle made by line fromeye of observer = 30°. BAC = 45° = angle of elevation100 feet nearer.From A draw AN _L to AB.In rt. A AAN,Z NAA = 30°,and Z NAA = 60°. .-. NA = 50 feet..-. AN = V(100)2 - (50)2= V7500 = 50 V3=…
Trigonometry · Surveying · Navigation
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