Download 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 
tan  
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 
1