# 9th Class Mathematics Angles and Their Measurement Concept of Angle in Geometry

## Concept of Angle in Geometry

Category : 9th Class

### Introduction

This is the one of the fundamental concept of "Trigonometry". Trigonometry is the branch of mathematics which deals with the measurement of sides and angles of a triangle. In modern days, its scope has been extended and it also includes the study of polygons and circles.

### Concept of Angle in Geometry

We know that a line is a geometrical shape which extended infinitely in both directions.

Suppose when a point P put anywhere in the above line, it will be converted into rays. These rays are responsible for the formation of an angle means "An angle is a geometrical figure made by two rays having common end point (called vertex)" these rays are called sides or arms of an angle. An angle is represented by S a symbol "<". The way to represent it put vertex in the middle.

$\angle \text{RPO},\angle \text{SPQ},\angle \text{RPS}$ are the angles with vertex P.

The inclination of one ray to other represented by a number is called measurement of an angle. One of the most important aspect of geometry is that all the angles are between $0{}^\circ$and$\text{36}0{}^\circ$ and there is no meaning of negative angle.

#### Other Topics

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