1. 5-Minute checks YZ

2. 7.6 Apply the sine and cosine ratios
Students will recognize and apply the sine & cosine ratios where applicable.
Why? So you can find distances, as seen in EX 39.
Mastery is 80% or better on 5-minute checks and practice problems.

3. Trigonometric Ratios- concept develop
Let ∆ABC be a right triangle. The since, the cosine, and the tangent of the acute angle A are defined as follows.
Side adjacent to A b
cos A = =
hypotenuse c
Side opposite A a
sin A = =
hypotenuse c
Side opposite A a
tan A = =
Side adjacent to A b

4. Example 1 – skill develop

5. Think ….Ink….Share

6. Example 2 Finding the Cosine – skill develop

7. Example 3 -HOTS Think….Ink….Share

8. Example 3 Solutions

9. With A pARTNER

10. Example 4 – hots Finding a Hypotenuse using an angle of depression

11. Example 4 solution

12. Check for understanding

13. Example 5 Find leg length using angles of elevation- real world application

14. Example 5 solution

15. Example 5 solution

16. Example 6 using special right triangles –guided practice & apk

17. Example 6 continued

18. Think …..Ink….Share
When looking for missing lengths & angle measures what is the determining factor in deciding to use Sin, Cos & Tan?
How do you know which on to use?

19. What was the objective for today?
Students will recognize and apply the sine & cosine ratios where applicable.
Why? So you can find distances, as seen in EX 39.
Mastery is 80% or better on 5-minute checks and practice problems.

20. Homework
PDF Sine, Cos & Tan Review Work Sheet
Online in the HW tab

21. Ex: 5 Using a Calculator
You can use a calculator to approximate the sine, cosine, and the tangent of 74. Make sure that your calculator is in degree mode. The table shows some sample keystroke sequences accepted by most calculators.

22. Sample keystrokes
Sample keystroke sequences
Sample calculator display
Rounded
Approximation 74
0.9613
0.2756
3.4874
sin
sin
ENTER 74
COS
COS
ENTER 74
TAN
TAN
ENTER

23. Trigonometric Identities
A trigonometric identity is an equation involving trigonometric ratios that is true for all acute triangles. You are asked to prove the following identities in Exercises 47 and 52.
(sin A)2 + (cos A)2 = 1
sin A
tan A =
cos A