8.7 Angles of Elevation and Depression

8-7 Applications of Right Triangle Trigonometry

Objective:

1. I can distinguish between the angle of depression and the angle of elevation.

Definition: The angle of depression is the angle below the horizontal line that an observer must look in order to see an object that is lower than the observer

Definition: The angle of elevation is the angle above the horizontal line that an observer must look in order to see an object that is higher than the observer

Example 1

tan 51 =ℎ

2121 ∙ tan 51 = ℎ21 ∙ 1.2349 = ℎ

26 ≈ ℎ

The tree is about 26 ft. tall.

Example 2

tan 10 =25

𝑥

𝑥 =25

tan10

𝑥 ≈ 142

The boat is about 142 m from the base of the lighthouse.