A treatise on surveying and navigation: uniting the theoretical, practical, and educational features of these subjects (1857)
Robinson, Horatio N[elson], 1806-1867. [from old catalog] · Cincinnati, J. Ernst; Toledo, Anderson, Burr, & co. · leaf 206
LEMMA. If the exterior angle of a triangle he bisected, and also one of theinterior opposite angles, and the bisecting lines produced until theymeet, the angle so formed will be half the other interior opposite angle. Let AB C be the triangle, and bisect the exterior angle A CDby the line CF, and… … THE PLANE TABLE. 203 resented in the figure ), andeach of the equal parts of theangle B by y. Let A repre-sent the angle A, and E theangle E. Now as the sum of the threeangles of every plane triangleis equal to 180°; therefore, in the the triangle ABO, we have -4+2y+C=180° (1) Also, in the triangle…
Surveying · Navigation
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