A surveying problem which asks: Determine the position of an unknown accessible point 
by its bearings from three inaccessible known points 
, 
, and 
.
Snellius-Pothenot Problem
See also
Hansen's ProblemExplore with Wolfram|Alpha
References
Dörrie, H. "Annex to a Survey." §40 in 100 Great Problems of Elementary Mathematics: Their History and Solutions. New York: Dover, pp. 193-197, 1965.Referenced on Wolfram|Alpha
Snellius-Pothenot ProblemCite this as:
Weisstein, Eric W. "Snellius-Pothenot Problem." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Snellius-PothenotProblem.html