Download 7-4 day 1

February 05, 2014
7-4 Trigonometry
Trigonometry (Trig):
*The study of triangle measurement.
*A way to find the length or angle measures for triangles.
Trigonometric Ratio (Trig Ratio):
*A ratio of the lengths of sides.
*Three most common trig ratios are
1. Sine (sin)
2. Cosine (cos)
3. Tangent (tan)
*The ratios relate to the acute angles in a right triangle
A
leg opposite to angle B
leg adjacent to angle A
hypotenuse
B leg opposite angle A C
leg adjacent to angle B
sin =
opp
hyp
cos =
adj
hyp
tan =
opp
=
adj
=
=
7-4 Trigonometry
leg opposite of angle
hypotenuse
leg adjacent to angle
hypotenuse
leg opposite of angle
leg adjacent to angle
February 05, 2014
7-4 Trigonometry
Trig ratios will also be used to find angle measures.
Watch how you use your calculator.
CHECk YOUR MODE!!!!!!!
Example 1
Find sin L, cos L, tan L, sin N,
cos N, tan N. Express each ratio
as a fraction and as a decimal to
the nearest thousandth.
sin L
sin N
cos L
cos N
tan L
N
8
M
17
15
tan N
Example 2
Express each ratio as a fraction.
X
35
tan Z =
sin X =
21
cos Z =
Z
Y
28
Example 3
Express each ratio as a fraction.
30
A
B
cos C =
sin A =
34
16
C
tan C =
L
February 05, 2014
7-4 Trigonometry
Example 4:
Find each value to the nearest ten thousandth.
a. tan 56
b. cos 89
Example 5
Solve for the variable
A.) sin B = 0.4848
B.) cos W = 0.6157
C.) tan x = 0.5317
Example 5
Z
Find each angle measure and round to the
nearest hundreth.
40
32
Y
24
X