## YesterdayiSaidTomorow 2 years ago Explain how to find the exact value of Sin 30°

.-9880316241 calculator click on sin(30) = .-9880316241

2. YesterdayiSaidTomorow

No. I said exact value.

it's probably -1 then

4. YesterdayiSaidTomorow

it's 1/2 but I keep on getting sqrt(3) / 2

5. akhaliq99

it is 1/2

6. YesterdayiSaidTomorow

Yes but how do you find it?

7. akhaliq99

look at until circle

8. akhaliq99

actually make a triangle

9. YesterdayiSaidTomorow

|dw:1359948962457:dw|

10. akhaliq99

then the sides are sqrt(3) and 1 is hypotunuse

11. YesterdayiSaidTomorow

How do you get 1/2?

12. akhaliq99

switch 1 and sqrt(3)

13. YesterdayiSaidTomorow

but why?

14. akhaliq99

to get 1/2 that is the triangle of 30 degrees look at this http://www.purplemath.com/modules/trig.htm

15. YesterdayiSaidTomorow

OOOOOOOOOH!! thanks!

16. akhaliq99

welcome

17. akhaliq99

memorize unit circle youll need it

18. YesterdayiSaidTomorow

I can't memorize stuff

19. akhaliq99

write it out once

20. akhaliq99

21. hammytams

my calculator says sin 30 is 0.5

22. YesterdayiSaidTomorow

help... how do I find sin120?

23. akhaliq99

sqrt(3)/2

24. YesterdayiSaidTomorow

but how? Shouldn't it be the same as sin30?

25. akhaliq99

use unit circle it will make life easy

26. akhaliq99

its a 30 60 90 triangle

27. akhaliq99

no sin of 150 is same as 30

28. YesterdayiSaidTomorow

|dw:1359950275904:dw|

29. YesterdayiSaidTomorow

s = o / h s = 1 / 2??

30. akhaliq99
31. akhaliq99

turn on coordinates

32. YesterdayiSaidTomorow

i don't want to memorize... i want to learn how to do it manually :(

33. YesterdayiSaidTomorow

what's wrong with my triangle? Is the right angle in the wrong place?

34. akhaliq99

yes it turned upside down

35. YesterdayiSaidTomorow

but why? don't you start at 0 degrees? From where do you start?

36. akhaliq99

this site should explain http://www.mathsisfun.com/sine-cosine-tangent.html

37. YesterdayiSaidTomorow

OH I GOT IT NOW! Thanks for the site!