8­4 Sine and Cosine Ratios 2011
February 09, 2011
8-4 Sine and Cosine Ratios
Obj: Use sine and cosine ratios to
find missing side lengths and angles
in right triangles.
Feb 2­12:06 PM
1
8­4 Sine and Cosine Ratios 2011
February 09, 2011
Warm-Up
1.Write the tangent ratios for
2. Find the value of:
A and
B
the side opposite
B
hypotenuse
3. Find the value of x. Round to the nearest tenth.
Feb 2­2:18 PM
2
8­4 Sine and Cosine Ratios 2011
February 09, 2011
Remember this...?
tan(A)
A
tan-1
Opposite
Adjacent
Opposite
( Adjacent )
Today we will look at other ratios found in triangles
Feb 2­2:32 PM
3
8­4 Sine and Cosine Ratios 2011
February 09, 2011
The Sine Ratio
A
sin-1
(
Opposite
Hypotenuse
)
Feb 2­2:32 PM
4
8­4 Sine and Cosine Ratios 2011
February 09, 2011
The Cosine Ratio
A
cos-1
(
Adjacent
Hypotenuse
)
Feb 2­2:32 PM
5
8­4 Sine and Cosine Ratios 2011
February 09, 2011
These are our three trig ratios.
In Greek, it
literally means
"triangle measurement".
Feb 2­2:36 PM
6
8­4 Sine and Cosine Ratios 2011
February 09, 2011
How are we going to remember these?
SOH
CAH
TOA
Feb 2­3:40 PM
7
8­4 Sine and Cosine Ratios 2011
February 09, 2011
Find the value of y:
y
Step 1: Which trig. ratio should you use?
0
30
23
Step 2: Set up a ratio.
Step 3: Solve.
Mar 5­11:25 AM
8
8­4 Sine and Cosine Ratios 2011
February 09, 2011
Find the value of x:
Step 1: Which trig. ratio should you use?
6 3
X
12
0
Step 2: Set up a ratio.
Step 3: Solve.
Mar 5­11:31 AM
9
8­4 Sine and Cosine Ratios 2011
February 09, 2011
Find the sine and cosine ratio of each angle.
sin(G) =
sin(T) =
cos(G) =
cos(T) =
Feb 27­11:38 AM
10
8­4 Sine and Cosine Ratios 2011
February 09, 2011
Homework
pg. 441 #1-9, 11-17 odd,
26, 41-43
Feb 2­3:01 PM
11