The angle of depression is the angle formed between a horizontal line and the line of sight to an object that is below the horizontal.
Think of it like this: Imagine you are standing on a hilltop looking down at a boat in the water. The horizontal line represents the ground level, and your line of sight is the angle at which you are looking down at the boat. The angle between these two lines is the angle of depression.
Here are some key points about the angle of depression:
- Always measured from the horizontal: The angle is always measured from a horizontal line, not from the vertical.
- Always below the horizontal: The angle of depression is always formed when you are looking down at an object, meaning the object is below the horizontal line.
- Complementary to the angle of elevation: The angle of depression is complementary to the angle of elevation. This means that the two angles add up to 90 degrees.
Example:
Imagine you are standing on a cliff 100 meters above sea level, looking down at a boat. The angle of depression from you to the boat is 30 degrees. This means that the line of sight from you to the boat makes a 30-degree angle with the horizontal line.
Practical Applications:
The angle of depression is used in various fields, including:
- Navigation: Sailors use it to determine the distance to objects on land.
- Surveying: Surveyors use it to measure the height of buildings or other structures.
- Aviation: Pilots use it to determine the angle of descent during landing.
