Trigonometry is one of the most important branch of mathematics.

The word trigonometry comes from the Greek words **trigonon** means “*triangle*” and **metron** means “*to measure*“.

Trigonometry is the study of the relation between the sides and angles of a right-angled triangle.

It helps in the calculation of the unknown dimensions of a right-angled triangle using formulas and identities based on this relationship.

## Definition

Trigonometry is the branch of mathematics that deals with the relationship between ratios of the sides of a right-angled triangle with its angles.

## Who is father of trigonometry?

**Hipparchus of Nicaea** (190-120 B.C) a Greek astronomer, mathematician and geographer. He is considered to be “**the father of trigonometry**“.

He created the first to construct a table of values for a trigonometric function and solved several problems of **spherical trigonometry** by representing the corresponding values of arc and chord for a series of angles such as 0°, 30°, 45°, 60° and 90°, etc.