Section 9 – 3 Angles of Elevation & Depression

Objectives:To use angles of elevation and depression to solve

problems

Angle of Elevation

The angle ABOVE a horizontal line

Angle of Depression

The angle BELOW a horizontal line

Angles ofElevation & Depression

Example 1 Identifying Angles of Elevation & Depression

Describe each angle as it relates to the situation shown.

A)∠1

B)∠4

C)∠2

D)∠3

Example 2 Trig Word ProblemsWrite a situation for each diagram. Then solve for the missing length or angle measure.

A)

B)

C)

D)

E)

HOMEWORK

Find missing angles & lengths for each word problem. Recognize how diagrams are drawn (tomorrow you will have to draw your own!)

Section 9 – 3Continued…

Objectives:To use angles of elevation and depression to solve

problems

Example 3 More Trig Word Problems

A) You sight a rock climber on a cliff at a 32°angle of elevation. The horizontal ground distance to the cliff is 1000 ft. Find the line-of-sight distance to the rock climber.

B) A surveyor stands 200 ft from a building to measure its height with a 5 ft high theodolite. The angle of elevation to the top of the building is 35°. How tall is the building?

C) A tree 30 feet high casts a shadow 45 feet long. Find the measure of the angle of elevation of the sun.

D) A flagpole is 26 feet high and the distance from the line of sight at the top of the flagpole to a person on the ground is 35 feet. What is the angle of depression?

E) An airplane flying 3500 feet about ground begins a 2° descent to land at an airport. How many miles from the airport is a point directly underneath the airplane when it starts its descent?

F) To approach runway 17 at the Ponca City Municipal Airport in Oklahoma, the pilot must begin a 3° descent starting from an altitude of 2714 feet. The airport altitude is 1007 feet. How many miles from the runway is the airplane at the start of this approach?

HOMEWORK

• Complete Trigonometry Word Problems Worksheet