1. Section 8.5 ~ Angles of Elevation & Depression!
L.T.: Be able to use the trig ratios with angles of elevation and depression! 1
Angle of Depression:
Angle going DOWN from a horizontal line! 2
Angle of Elevation:
Angle going UP from a horizontal line!
Recall: Alternate interior angles are _____.
So, the angle of depression _____ the angle of elevation.

2. Let’s practice! 65˚ x 65˚ 900 ft 1 and 3 2 and 4
Ex. 1: Describe each angle as it relates to the picture shown. 1 4 3 2
Ex. 2: The angle of depression from the Goodyear Blimp to home plate at Busch Stadium is 65˚. If the ground distance from the blimp to the plate is 900 feet, what is the altitude of the blimp?
65˚ x
65˚
900 ft
Angles of depression:
Angles of elevation:
1 and 3
2 and 4

3. Would it be okay if we just do the homework now? 
1. A slide has an angle of elevation of 25˚. It is 60 feet from the end of the slide to the stairway beneath the top of the slide. How long is the slide?
25˚
60 ft x
2. A forester is standing 150 feet away from a tree. She measures the angle of elevation from where she is to the top of the tree to be 30˚. How tall is the tree? x
30˚
150 ft

4. 3. A moving sidewalk takes zoo visitors up a hill
3. A moving sidewalk takes zoo visitors up a hill. The vertical distance of the sidewalk is 48 feet. Its angle of elevation is 15˚. About how long is the sidewalk? x
48 ft
15˚
6. An airplane flying 4000 feet above ground begins a 2˚ descent (angle of depression) to land at an airport. How many miles from the airport is the plane when it starts its descent? (Hint: 1 mile = 5280 feet) 2˚
4000 ft. x 2˚

5. 7. A 100-foot-tall lighthouse stands at the top of a 150-foot-tall cliff. The angle of depression from the top of the lighthouse to a ship is 27˚. About how far from the cliff is the ship?
100 ft
250 ft
150 ft
27˚ x
10. A building is 50 feet high. At a distance away from the building, an observer notices that the angle of elevation to the top of the building is 41º. How far is the observer from the base of the building?
50 ft
41˚ x

6. 11. An airplane is flying at a height of 2 miles above the ground
11. An airplane is flying at a height of 2 miles above the ground. The distance along the ground from the airplane to the airport is 5 miles. What is the angle of depression from the airplane to the airport?
2 mi x˚
5 mi
13. A campsite is 9.41 miles from a point directly below the mountain top. If the angle of elevation is 12° from the camp to the top of the mountain, how high is the mountain? x
12˚
9.41 mi