# Use Trigonometric ratio to calculate Height and Distances

**Line of Sight **: A straight line draws from observer eye to any object that observe by observer is known as line of sight.

**Angle of Elevation **: angle between line of sight and horizontal line from observer eye is known as angle of elevation.

**Angle of Depression **: if observer seeing downward then the angle between horizontal line from observer eye and line of sight is known as angle of depression.

**Angle of Elevation = Angle of Depression**

We can use Trigonometric ratio sin , cos , tan as per requirement if height is given and you need to find distance then use tan with Angle of Elevation/depression

We know that

Sinθ = perpendicular/Hypotenuse

Cosθ = Base/ Hypotenuse

tan θ = perpendicular/Base

## How to calculate height

Example: The angle of elevation of the top of a tower at a distance of 100 meter from its foot on a horizontal plane is found to be 60 degree then find height of tower.

In triangle ABC tan60 = AB/BC

tan 60=AB/100

√3=AB/100

AB(height of tower)= 100√3