Trigonometry (from Greek trigōnon, "triangle" + metron, "measure") is a branch of mathematics that studies relationships involving lengths and angles of triangles. The field emerged during the 3rd century BC from applications of geometry to astronomical studies,

The 3rd-century astronomers first noted that the lengths of the sides of a right-angle triangle and the angles between those sides have fixed relationships: that is, if at least the length of one side and the value of one angle is known, then all other angles and lengths can be determined arithmetically.

This document will discuss the Sine Cosine and Tangent identities as well as the well-known Pythagorean formula for a right angled triangle, but to start off we should discuss some basics.