10.2 – Using the
calculator
Change the Mode to Degrees
Finding the trig value
sin(45 ) 
cos(60 ) 
1
csc(30 ) 
sin(30 )
1
cot(30 ) 
tan(30 )
Find the trig value for each angle:
1. cos(26 ) 
0.8988
1. cos(90 )  0
2. sin(73 ) 
0.9563
2. sin(90 ) 
3. csc(29 ) 
2.0627
3. tan(90 )  Undefined
4. tan(23 ) 
0.4245
4. sin(120 )  0.8660
5. sec(77 )  4.4454
6. cot(66 )  0.4452
1
5. cos(120 )  0.5
6. tan(120 )  1.7321
Using trig functions to solve
70
y
𝑧
12
12
sin(70 ) 
y
12
y
sin(70 )
12
tan(70 ) 
z
12
z
tan(70 )
y  12.7701
z  4.3676
Word Problem
A nursery plants a new tree and attaches
a guy wire to help support the tree while
its roots take hold. An eight foot wire is
attached to the tree and to a stake in the
ground. From the stake in the ground the
angle of elevation of the connection with
the tree is 42º. Find to the nearest tenth
of a foot, the height of the connection
point on the tree.
sin?
cos?
tan?
x
sin(42 ) 
8
x  8  sin(42 )
x  5.4 feet
Going backwards (Inverse trig functions)
Inverse trig functions return the angle for a
given ratio of sides
sin( )  x  sin ( x )  
1
cos( )  x  cos1( x )  
tan( )  x  tan ( x )  
1
3
1  3 
sin( )   sin    
5
5
5
3
𝜃
4
  36.87
4
1  4 
cos( )   cos    
5
5
  36.87
3
1  3 
 tan    
tan( ) 
4
4
  36.87
You are standing looking at
a painting on the wall The
bottom of the painting is 1
foot above your eye level.
The painting is 10 feet tall.
If you are standing 10 feet
from the painting what is
the angle formed by the
lines of vision to the
bottom and to the top of
the painting?