CHAP, v.] 



CALCULATING POSITION, ETC. 



171 



formed by the objects ; when he is outside, and the centre 

 object is nearer than one of the others ; and when, under 

 similar circumstances, it is the farthest. 



If the angles betAveen the three objects are known, which 



is most probable, the calculation of the second formula will 

 be unnecessary. 



Let A B C be the objects observed. X the position of 

 observer to be determined. AB = c, BC = a, AC = &, are the 

 sides known, A X B = m and B X C = w, the angles observed. 

 Required X A and the angle B A X. 



At A, in A C, draw, on the side remote from X, A D, making 



