Transcript WARM UP - bYTEBoss

Section 8.7
Real Life Applications
of Trigonometry
TWO Types of Angles

Angle of elevation: angle between
the horizontal and the line of sight of
the observer above the horizon.
TWO Types of Angles

Angle of depression: the angle
between the horizontal and the line
of sight of the observer beneath the
horizontal
Lighthouses
1) The top of a lighthouse is 25 m above sea
level. A person in a sailboat must look up
2 degrees from the horizon to see the top
of the lighthouse. Find the distance
between a sailboat and the base of the
lighthouse.
Lighthouses
1) The top of a lighthouse is 25 m above sea level. A person in a sailboat
must look up 2 degrees from the horizon to see the top of the lighthouse.
Find the distance between a sailboat and the base of the cliff beneath the
25
tan 2 
x
25
0.0349 
x
25
0.0349  x 
x
x
0.0349x  25
x  715.9
25 meters
lighthouse.
2o
x meters
SHADOWS
2)
The sun’s angle of depression
is 38 degrees and a building
casts a shadow of 45 m. How
high is the building?
SHADOWS
2)
The sun’s angle of depression is 38 degrees and a building
casts a shadow of 45 m. How high is the building?
x
tan 38 
45
x
0.781 
45
38
Angle of depressiono
x
0.781 45   45
45
35.145  x
x meters
38o
45 meters
LADDERS!
12) A 6 m ladder reaches higher
up a wall when placed at a 70
degree angle than when placed
at a 60 degree angle.
How much higher, to the nearest
tenth of a meter?
LADDERS!
12) A 6 m ladder reaches higher up a wall when placed at a 70 degree
angle than when placed at a 60 degree angle.
How much higher, to the nearest tenth of a meter?
o o
60
60oo7070
LADDERS!
12) A 6 m ladder reaches higher up a wall when placed at a 70 degree angle
than when placed at a 60 degree angle.
How much higher, to the nearest tenth of a meter?
x
y
60o
60o 70o
70o
y
y
x
x
sin 60 5.6382
0.866

– 5.196 = 0.4422
ft 
sin 70 = 0.4
0.9397
6
6
6
6
5.196 ft  y
5.6382 ft  x
Practice
 Page
317 – 318
 Classroom Exercises
 #1 – 7