1. Welcome
GCSE Maths

3. What is x?

4. What is x?

5. What is ‘a’?

6. Trigonometry
We can use trigonometry to find missing angles and lengths of triangles
Trigonometry uses three functions, these are called:
Sine (shortened to Sin and pronounced “sign”)
Cosine (shortened to Cos)
Tangent (shortened to Tan)
We will start working with right angled triangles

7. Labelling the sides Hypotenuse
Before we can use Sin, Cos and Tan we need to be able to label the sides of a right angled triangle
The longest side, the one opposite the right angle, is called the Hypotenuse
Hypotenuse

9. But if we are working with this angle, we label the sides like this...
What we call the other two sides will change depending on which angle we are working with, for example..
If we are given (or need to work out) this angle, we label the other sides like this..
Opposite
Adjacent
But if we are working with this angle, we label the sides like this... ϴ
Opposite
Adjacent

10. What is the side marked with an X?ϴ
Adjacent
Opposite
Hypotenuse

11. What is the side marked with an X?ϴ X
Adjacent
Opposite
Hypotenuse

12. What is the side marked with an X?ϴ
Adjacent
Opposite
Hypotenuse

13. What is the side marked with an X?ϴ X
Adjacent
Opposite
Hypotenuse

14. What is the side marked with an X?ϴ
Adjacent
Opposite
Hypotenuse

15. What is the side marked with an X?ϴ
Adjacent
Opposite
Hypotenuse

16. Stages for Trigonometry in right-angled triangles
Label sides
Decide on formula to use
Write formula
Calculate formula, (do the sum)
Write your answer as stated in the question.
Triangles of knowledge

17. Triangles of knowledge
SIN
COS
TAN

18. Example 1 7cm x Label sides Decide on formula to use Write formula
42˚
7cm x
Label sides
Decide on formula to use
Write formula
Calculate formula, (do the sum)
Write your answer as stated in the question.

19. Example 2 9cm t Label sides Decide on formula to use Write formula
53˚
9cm t
Label sides
Decide on formula to use
Write formula
Calculate formula, (do the sum)
Write your answer as stated in the question.

20. Example 3 y 11cm Label sides Decide on formula to use Write formula
53˚
11cm y
Label sides
Decide on formula to use
Write formula
Calculate formula, (do the sum)
Write your answer as stated in the question.

21. Example 4- what to do if finding an angle
Label sides
Decide on formula to use
Write formula
Calculate formula, (do the sum).
Write your answer as stated in the question.
8cm
5cm X

22. what to do if finding an angle
Example 5
what to do if finding an angle
Label sides
Decide on formula to use
Write formula
Calculate formula, (do the sum)
Write your answer as stated in the question. X
32 cm
56 cm

23. Applying the knowledge
Matching activity
Revision workbook
Exam style questions
Remember the stages…
Label sides
Decide on formula to use
Write formula
Calculate formula, (do the sum)
Write your answer as stated in the question.

25. Reflection What went well? What could be better? What did I learn?
What still puzzles me?