New plane and spherical trigonometry, surveying, and navigation (1903)
Wentworth, G. A. (George Albert), 1835-1906 · Boston : Ginn & Company · leaf 57
AN= 86.60AB = 273.20 = cot NBA= cot lo° 48 PLANE TKIGOXOMETRY. In rt. A ABC,Z BAC = 30°,and Z ABC = 60°..-. BC = iAB = i x 273.20 feet= 136.60 feet. 65. From a certain point on theground the angles of elevation ofthe belfry of a church and of the topof a steeple were found to be 40°and 51°… … = sin 33° 45. 300 ft. Draw DE _L to AB from D.In A BED, ED BD .-. ED = 300 x sin 33° 45.log 300 = 2.47712log sin 33° 45= 9.74474log ED = 2.22186Z EAD = 180° - 33° 45 - (180°- 51°) = 17° 15.In A ADE,ED AD = sin 17° 15. log .EDcologsin 17° 15log^iDIn A^iDC, DC AD r.DC log AD log cos 51° log DC In A…
Trigonometry · Surveying · Navigation
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