1. Subject
Mathematics (F.2)

2. PROJECT TITLE
Trigonometric Ratios

3. Target Audience
F.2 Students

4. How Slides are going to be used ?
The Slide are going to be used during lesson

5. A computer with the following software installed
System Requirement
A computer with the following software installed
Power Point 97/2000

6. Trigonometric Ratios Contents Introduction to Trigonometric Ratios
Unit Circle
Adjacent , opposite side and hypotenuse of a right angle triangle.
Three types trigonometric ratios
Conclusion

7. Introduction Trigonometric Ratios
Trigonometry (三角幾何) means “Triangle” and “Measurement”
In F.2 we concentrated on right angle triangles.

8. Unit Circle
A Unit Circle Is a Circle With Radius Equals to 1 Unit.(We Always Choose Origin As Its centre)
1 units x Y

9. Adjacent , Opposite Side and Hypotenuse of a Right Angle Triangle.

10. 
Opposite side
hypotenuse
Adjacent side

11. 
hypotenuse
Adjacent side
Opposite side

12. Three Types Trigonometric Ratios
There are 3 kinds of trigonometric ratios we will learn.
sine ratio
cosine ratio
tangent ratio

13. Definition of Sine Ratio. Application of Sine Ratio.
Sine Ratios
Definition of Sine Ratio.
Application of Sine Ratio.

14. Definition of Sine Ratio.
Opposite sides 1
If the hypotenuse equals to 1
Sin =

15. Definition of Sine Ratio.
Opposite side
hypotenuses
For any right-angled triangle
Sin =

16.  Exercise 1 In the figure, find sin  4 Opposite Side Sin = 7
hypotenuses 4 = 7
 =  (corr to 2 d.p.)

17. 35° Exercise 2 In the figure, find y y Opposite Side Sin35 =
hypotenuses
35° 11 y
Sin35 = 11
y = 11 sin35
y = (corr to 2.d.p.)

18. Cosine Ratios Definition of Cosine.
Relation of Cosine to the sides of right angle triangle.

19. Definition of Cosine Ratio. 1
Adjacent Side
If the hypotenuse equals to 1
Cos =

20. Definition of Cosine Ratio.
hypotenuses
Adjacent Side
For any right-angled triangle
Cos =

21.  Exercise 3 3 In the figure, find cos  adjacent Side cos = 8
hypotenuses 3 = 8
 =  (corr to 2 d.p.)

22. 42° Exercise 4 In the figure, find x 6 Adjacent Side Cos 42 =
hypotenuses x 6
Cos 42 = x 6
x =
Cos 42
x = (corr to 2.d.p.)

23. Tangent Ratios Definition of Tangent.
Relation of Tangent to the sides of right angle triangle.

24. Definition of Tangent Ratio.
Opposite Side 
Adjacent Side
For any right-angled triangle
tan =

25.  Exercise 5 3 In the figure, find tan  Opposite side 5 tan =
adjacent Side  3 = 5
 =  (corr to 2 d.p.)

26. 22 Exercise 6 In the figure, find z z Opposite side tan 22 =
adjacent Side 5 5
tan 22 = z 5
z =
tan 22
z = (corr to 2 d.p.)

27. Make Sure that the triangle is right-angled
Conclusion
Make Sure that the triangle is right-angled

28. END