In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points.
A triangulation station signed by iron rod
Measuring the height of a building with an inclinometer
Trigonometry is a branch of mathematics concerned with relationships between angles and side lengths of triangles. In particular, the trigonometric functions relate the angles of a right triangle with ratios of its side lengths. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. The Greeks focused on the calculation of chords, while mathematicians in India created the earliest-known tables of values for trigonometric ratios such as sine.
Hipparchus, credited with compiling the first trigonometric table, has been described as "the father of trigonometry".