Sumerian astronomers studied angle measure, using a division of circles into 360 degrees. They, and later the Babylonians, … See more

Trigonometric ratios are the ratios between edges of a right triangle. These ratios depend only on one acute angle of the right triangle, since any two right triangles with the same acute angle are similar.
So, these r… See more

Using the unit circle, one can extend the definitions of trigonometric ratios to all positive and negative arguments (see trigonometric function).
The following table summarizes the properties … See more

For centuries, spherical trigonometry has been used for locating solar, lunar, and stellar positions, predicting eclipses, and describing the orbits of the planets.
In modern times, the technique of triangulation is … See more