Hansen's Problem

A Surveying Problem: from the position of two known but inaccessible points $A$ and $B$, determine the position of two unknown accessible points $P$ and $P'$ by bearings from $A$, $B$, $P'$ to $P$ and $A$, $B$, $P$ to $P'$.

See also Surveying Problems

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.