Transcript Document

4.3 Right Triangle Trigonometry
It’s
for Trigonometric
Functions and Right
Triangles.
opposite 90  
side

adjacent side
Ex.
Find the six trig. functions of theta.
h=5
4

3
Quotient Identities
sin 
t an 
cos
cos
cot 
sin 
4
sin  
5
3
cos 
5
4
tan 
3
5
csc 
4
5
sec 
3
3
cot 
4
Pythagorean Identities
sin   cos   1
2
2
1  tan   sec 
2
2
1  cot   csc 
2
2
Ex.
Use a calculator to evaluate
sec540'12"
First, change the deg, min, sec, to a decimal.
40
12
5


60 3600
5.67 
1
sec 5.67 
 1.00492
cos 5.67
Note: Make sure your calculator is in degree mode.
Find the height of the tree if a surveyor is 50 ft.
from the base of the tree and measures the angle
of elevation to the top of the tree as 71.5o.
h
tan 71 .5 
50
h  149.4 ft.
h
71 .5
50’
A 40 ft. flag pole casts a 30 ft. shadow. Find the
angle of elevation.
40
tan  
30
40’

30’
To find
 , take the INV tan.
 40 
tan    53 .13 
 30 
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