There is a very general idea that when plotting three bearings and they fail to cross in a point, that the probable position is the middle of the triangle so formed, and that an error in one bearing has probably been made.
Taking an exaggerated case, A, B and C being points on shore, DA-DB-EC, the plotted bearings forming the triangle DEF.
Consider the bearings taken as representing horizontal angles, then a circle through ABD will give all possible positions of D. A circle through BCE will give all possible positions of E.
The point of crossing of the two circles at G will be the position required, and the angle DAG will be the compass error that should have been applied to each of the bearings so that they would cross in a point.
An inspection of the triangle will easily give the intersection without actually drawing the circle.
When the bearing of the center object cuts to the right of the intersection of the other two bearings, the position is to the right of the triangle; and when it cuts to the left, the position is to the left of the triangle.