In mathematics, biangular coordinates are a coordinate system for the plane where C 1 {\displaystyle C_{1}} and C 2 {\displaystyle C_{2}} are two fixed points, and the position of a point P not on the line C 1 C 2 ¯ {\displaystyle {\overline {C_{1}C_{2}}}} is determined by the angles ∠ P C 1 C 2 {\displaystyle \angle PC_{1}C_{2}} and ∠ P C 2 C 1 . {\displaystyle \angle PC_{2}C_{1}.}
The sine rule can be used to convert from biangular coordinates to two-center bipolar coordinates.
Applications Biangular coordinates can be used in geometric modelling and CAD.
See also Two-center bipolar coordinates Bipolar coordinates Sectrix of Maclaurin
References
External links G. B. M. Zerr Biangular Coordinates, American Mathematical Monthly 17 (2), February 1910 J. C. L. Fish, Coordinates Of Elementary Surveying George Shoobridge Carr, A synopsis of elementary results in pure mathematics (see page 742)