TRANSACTIONS 



OF THE 



SOUTH AFRICAN PHILOSOPHICAL SOCIETY 



NOTE ON THE THREE-POINT, OR POTHENOT'S, 



PROBLEM. 



By H. G. Foukcade. 



(Read January 27, 1897.) 



The ordinary methods of computation of the position of a point, 

 given the angles subtended by three other points of known positions 

 are chiefly : — 



First method. 



»B 1. Compute the length and " angle 

 of direction" of a from the co-ordi- 

 / nates of C and A. 



2. Compute the length and angle of 

 direction of /3 from C and B. 



3. Put PAC = £, PBC = #. Then 

 tan J (x — y) = tan (z — 45°) tan i(x-\-y) 



Where 



a sin /3 



Pi 



fiS 



tan z — 



b sin a 



and 



l(^ + 7/) = 180°-|(a + /3 + C). 



si 3 



