Triangulation Calculator

Triangulation determines an unknown position by constructing a triangle from a measured baseline and observed angles. In the angle-side-angle case, the baseline joins two known stations and the observer measures an angle from each endpoint toward the target. Those three measurements completely determine one triangle, so the target distances can be calculated without measuring either distance directly. This practical geometric method has long supported land surveying, navigation, cartography, astronomy, engineering, and field measurement. The calculator labels the known baseline as side c. Angle A and angle B sit at the two endpoints of that baseline, while angle C is opposite it. Because every triangle has an interior angle sum of 180 degrees, the first calculation is C = 180 - A - B. The inputs must therefore be positive and A + B must remain below 180. A sum near 180 produces a very shallow triangle, where small measurement errors can create large changes in the computed distances. After finding C, the calculator applies the Law of Sines: a / sin(A) = b / sin(B) = c / sin(C). Rearranging gives a = c × sin(A) / sin(C) and b = c × sin(B) / sin(C). The browser converts degree measurements to radians before evaluating sine. Results retain useful decimal precision while remaining easy to read. The baseline can use metres, feet, kilometres, or any other length unit; the calculated sides automatically use that same unit. Good triangulation depends on good observations. Use the longest accurately measured baseline that the site permits, identify its endpoints clearly, and measure each angle consistently. Avoid configurations where the target is almost in line with the baseline because narrow intersection angles magnify error. Repeated readings and observations from additional stations improve confidence in professional work. Triangulation should not be confused with trilateration. Triangulation primarily uses angles from known points, whereas trilateration uses measured distances from several known points. Satellite navigation is commonly described through trilateration, while a surveyor observing a distant marker with a theodolite demonstrates classic triangulation. This calculator focuses specifically on one deterministic ASA triangle and provides a transparent Law of Sines result.