**Definition of Angle of Depression**

The word “depression” means “fall” or “drop”.

Angle of depression is the angle between the horizontal and the line of sight to an object beneath the horizontal.

Take a look at the example below.

In the picture below, an observer is standing at the top of a building and looking straight ahead at the birds (horizontal line). The observer must lower his eyes to see the car parked (slanting line).

The angle formed between the **two lines** is called the angle of depression.

**Solved Example on Angle of Depression**

An airplane is flying at a height of 2 miles above the level ground. The angle of depression from the plane to the foot of a tree is 15°. Find the distance that the air plane must fly to be directly above the tree.

**Solution:**

**Step 1:** Let’s first visualize the situation.

**Step 2:**** **Let ‘*x*’ be the distance the airplane must fly to be directly above the tree.

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**Step 6:**** **So, the airplane must fly about 7.46 miles to be directly above the tree.

- Angle
- Horizontal Line