Calculate coordinates (linear resection from three stations)

It is necessary for user to specify three initial points on a map. Then in the corresponding dialogue to enter parameters of construction (distance up to a created point from each of the specified points). Coordinates of a picket point are on crossing of the segments dropped from each picket. Lengths of segments are specified by the user. As the program carries out equalizing the variant of too big error is possible at equalizing (adjustment), thus, the corresponding message will be given out.  

It is necessary for user to enter value of measures of lines approximately corresponding to a specified task.  

See terms.