1. Introduction to Trigonometry
Introduction to Trigonometry
L.O.
All pupils can identify the different sides of right angled triangles
All pupils understand the phrase SOHCAHTOA
All pupils can use SOCAHTOA

2. Starter:
Draw a straight line across the middle of your page – anywhere between 6 and 15cm
At one end draw a right angle and continue the line up your page
At the other end draw a 30 degree angle (towards the middle of your page) and continue this line until it meets your other line
You should have now created a right angled triangle

3. Starter:
Opposite
Hypotenuse
Ratio

4. Introduction to Trigonometry
L.O.
All pupils can identify the different sides of right angled triangles
All pupils understand the phrase SOHCAHTOA
All pupils can use SOCAHTOA

5. identify the different sides of right angled triangles
Main 1:
identify the different sides of right angled triangles
Trigonometry is a collection of methods we can use to find out information on right angled triangles.

6. identify the different sides of right angled triangles
Main 1:
identify the different sides of right angled triangles
One technique that is used a lot is often called SOHCAHTOA. SOHCAHTOA is used to find missing lengths or angles in right angled triangles.

7. identify the different sides of right angled triangles
Main 1:
identify the different sides of right angled triangles
To use the SOHCAHTOA technique, you must have a right angled triangle and two other pieces of information.

8. identify the different sides of right angled triangles
Main 1:
identify the different sides of right angled triangles x
Hypotenuse
Opposite
Adjacent

9. Label the following triangles…
Main 1:
Label the following triangles…
identify the different sides of right angled triangles

10. Introduction to Trigonometry
L.O.
All pupils can identify the different sides of right angled triangles
All pupils understand the phrase SOHCAHTOA
All pupils can use SOCAHTOA

11. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
The slide from our starter activity:
We noticed all the ratios are constant – could we use this to our advantage?

12. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
When you're given and angle and given a side
I begin to complain she says Shut Up use SohCahToa
This phrase may save my grade
She says oh, oh, oh, Shut Up use SohCahToa
Right Triangles and some missing sides
This problem will continue to blow my mind
I felt it in my brain as she looked aside
I put my Calc. in degree mode, my Calc. in degree mode
She took my arm, I don't know how it happened.
We hit the books and she said...

13. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
SOH CAH TOA

14. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
Sine, Cos or Tan?
Answer: Tan
You know the adjacent and want the opposite. x
35o 7

15. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
Sine, Cos or Tan?
Answer: Sin
You know the opposite and want the hypotenuse. x 10
40o

16. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
Sine, Cos or Tan?
Answer: Cos
You know the adjacent and want the hypotenuse.
35o x 20

17. Sine, Cos or Tan? Answer: Sin x 12 38o S H O C H A T A O
You know the hypotenuse and want the opposite. x 12
38o
S H O
C H A
T A O

18. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
Sine, Cos or Tan?
Answer: Sin
You know the opposite and the hypotenuse. You want to find the angle. 18 10 o

19. understand the phrase SOHCAHTOA
Main 2:
Sine, Cos or Tan?
understand the phrase SOHCAHTOA
Answer: Sin
You know the opposite and the hypotenuse. And want to know the angle 15 10 o

20. Sine, Cos or Tan? Answer: Cos 21o x S H O C H A T A O
You know the hypotenuse and want the adjacent.
21o
100 x
S H O
C H A
T A O

21. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
Sine, Cos or Tan?
Answer: Tan
You know the opposite and want the adjacent. 24
37o x

22. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
Sine, Cos or Tan?
Answer: Tan
You know the opposite and want the adjacent. 20
42o x

23. understand the phrase SOHCAHTOA
Main 2:
understand the phrase SOHCAHTOA
Sine, Cos or Tan?
Answer: Sin
You know the opposite and the hypotenuse. You want to find the angle.
400
200 o

24. Introduction to Trigonometry
L.O.
All pupils can identify the different sides of right angled triangles
All pupils understand the phrase SOHCAHTOA
All pupils can use SOCAHTOA