# Definitions in Trigonometry

There are different terminologies used in trigonometry are:-

## Angle

The angle is an arc which shows the exposure between two arms.

In the above figure exposure between arm BA & BC is an angle ABC.

## Ratio

It is a fraction for any two sides of a right angle triangle.

## Angle of elevation

When a point makes an angle with the horizontal axis to the top of any object then the angle is known as Angle of Elevation.

## Angle of depression

When a point makes an angle from the top with a horizontal axis to any below object (point) then the angle is known as Angle of Depression.

## Line of Sight

Line of sight is a line which shows the direction of angle from the horizontal line.