13-1B
Solving a Rt Triangle &
Angles of Elevation &
Depression
Alg. II
Solving a Triangle -Find 3 missing
parts, angle & side lengths
•
• Ex. 1) Given A = 35 degrees , c = 16
Vocabulary

Angle of Depression
and Angle of
Elevation are Equal
by AIA Thm because
horizontal lines are ll.
Horizontal Line
Angle of Depression
Angle of Elevation
Horizontal Line
Identifying Angles of
Elevation and Depression
1 is the angle of depression
2 is the angle of elevation
1
2
#2 Real-World Connection

You sight a rock climber on a cliff at a 32o
angle of elevation. The horizontal ground
distance to the cliff is 1000 ft. Find the line of
sight distance to the rock climber.
1000
Cos 32 
x
x
1000
x
Cos 32
x  1179 ft
32
1000 ft
#3 Real-World Connection

An airplane pilots sights a life raft at a 26o
angle of depression. The airplane’s altitude is
3 km. What is the airplane’s surface distance
d from the raft?
3
Tan 26 
d
3
d
Tan 26
d  6.2 km
26
3 km
26
d
#4 Real World Connection

You are standing at the end of the
shadow of a giant sequoia, 150 ft from
its base. The angle of elevation to the
sun is 63 degrees. How tall is the
tree?