Some Applications of Trigonometry Full Video || Chapter – 9 || Class 10th (For Hindi Medium)

__Heights and Distances__

Horizontal Level and Line of Sight

**Line of sight and horizontal level**

**Line of sight** is the line drawn from the eye of the observer to the point on the object viewed by the observer.

**Horizontal level** is the horizontal line through the eye of the observer.

To know more about Height and Distance, visit here.

**Angle of elevation**

The **angle of elevation** is relevant for objects above horizontal level.

It is the **angle** formed by the **line of sight** with the **horizontal level**.

**Angle of elevation**

To know more about Angle of elevation, visit here.

**Angle of depression**

The **angle of depression** is relevant for objects below horizontal level.

It is the **angle** formed by the **line of sight** with the **horizontal level**.

Angle of depression

To know more about Angle of depression, visit here.

Calculating Heights and Distances

To, calculate heights and distances, we can make use of trigonometric ratios.

**Step 1**: Draw a **line diagram** corresponding to the problem.

**Step 2**: Mark all known heights, distances and angles and denote unknown lengths by variables.

**Step 3**: Use the values of various **trigonometric ratios** of the angles to obtain the unknown lengths from the known lengths.

To get solved problems on Heights and Distances, visit here.

Be More Curious

**Measuring the distances of Celestial bodies with the help of trigonometry**

Large distances can be measured by the **parallax method**. The **parallax angle** is half the angle between two line of sights when an object is viewed from two different positions. Knowing the parallax angle and the distance between the two positions, large distances can be measured.