Transcript Angles of Elevation and Depression

Section 9-3: Angles of Elevation
and Depression
April 17, 2012
Warm-up: (20 mins)
 Practice 9-1 and 9-2: odd problems
 Challenge: Describe some real-world
applications of trigonometry
Warm-up: (20 mins)
Warm-up: (20 mins)
Warm-up: (20 mins)
Warm-up: (20 mins)
Questions on Homework?
Section 9-3:
Angles of Elevation and Depression
Objective: Today you will learn to identify
angles of elevation and depression
and use them with trigonometric
ratios to solve problems.
Angles of Elevation and Depression
Angles of elevation and depression are created by the horizontal
lines formed by a person’s line of sight to an object.
If a person is looking up, the angle is an elevation angle. If a
person is looking down, the angle is a depression angle.
Angles of Elevation and Depression
Examples with pictures
Examples with pictures
Examples with pictures
6.
Examples in words
7. A blimp is flying 500 ft above the ground. A person on
the ground sees the blimp by looking up at a 250 angle.
The person’s eye level is 5 ft above the ground. Find the
distance from the blimp to the person to the nearest foot.
8. A surveyor stands 200 ft from a building to measure its
height with a 5 ft tall theodolite. The angle of elevation to
the top of the building is 350. How tall is the building?
9. You see a rock climber on a cliff at a 320 angle of
elevation. The horizontal ground distance to the cliff is
1000 ft. Find the line-of-sight distance to the rock climber
to the nearest tenth of a foot.
Examples in words
10. An airplane flying 3500 ft above ground
begins a 20 descent to land at an airport. How
many miles from the runway is the airplane when
it starts its descent?
11. Two buildings are 30 ft apart. The angle of
elevation from top of one to the top of the other
is 190. What is their difference in height?
Examples in words
12. In a galaxy far, far away, a spaceship is
orbiting the planet Obar. The ship wants to land
in a large, flat crater, but the captain of the ship
wants to make sure the crater is large enough to
hold the ship. When the ship is 4 miles above
the planet, the onboard guidance system
measures the angles of depression from the ship
to both sides of the crater. The angles measure
220 and 370 respectively. What is the distance
across the crater? If the spaceship is 2500 ft
long, will it fit in the crater?
Wrap-up
 Today you learned to identify angles of elevation
and depression and use them with trigonometric
ratios to solve problems.
 Tomorrow you will learn to use trigonometric
ratios to find the area of polygons.
Homework (H)
 p. 484, #1 – 21, 23, 28, 33, 34
Homework (R)
 p. 484, #1 – 21, 23, 33