Trigonometry is the branch of the maths that develops from simple rules. Trigonometry is the branch of geometry that deals with the study of triangles. In triangle there are six basic elements: three sides and three angles. In trigonometry the relationships between the sides and angles of the triangle is studied. In trigonometry the key area of the study is the right triangles. Right triangles are the triangles with one angle of 90 degree. The word trigonometry is originated from two Greek words trigono and matron. Trigono means triangle and matron means measure. The very first trigonometric function is formalized by Greek. Trigonometry is very old science. It was used in its basic form in ancient Egypt.

There are six basic trigonometric functions in modern mathematics. These functions are also called trigonometric formula. These six functions are named as Sine, Tangent, Cosine, Secant, cotangent and cosecant. There are algebraic equations that are used to study triangle. These algebraic equations are called trigonometric identities. Pythagorean identities, reduction formulas and co function identities are the most common trigonometric identities. Trigonometry is basically used to cover the study topics like how to use the trigonometric function to solve the right angle triangles. And if the triangle is not right angle then sine and cosine trigonometric functions are used to solve it. Use of the trigonometry in real life varies. Engineers use it in industrial field in the course of their work. Other professionals who use trigonometry include surveyors, astronomers, architects and pilots.

Trigonometry is used to work out of the measurement of the things or space which is difficult to measure directly. Like it is used to measure the height of the mountains or the quantity of water in lake. It can also be used by astronomers to measure time accurately. Spherical trigonometry is very important in the study of the earth measurement. Because the earth is a sphere so in order to get the distance from one point of the earth to other the sphere trigonometry is used. Plane trigonometry is used to calculate the height without climbing on it like flagpole and skyscraper.