## BeccaB003 one year ago Help with lengths. Thanks!

1. BeccaB003

2. Nnesha

$\rm sin \rm \theta = \frac{ opposite }{ hypotenuse }~~~~ \cos \theta = \frac{ adjacent }{ hypotenuse } ~~\tan \theta = \frac{ opposite }{ adjacent }$

3. BeccaB003

I need to calculate the length of NO. I know how to work these problems EXCEPT I don't know whether to use sin cos or tan.

4. Nnesha

alright as you can the functions i posted hve 3 variables so to find NO you should know one angel and one side so we have to use sin $\huge\rm sin(60)= \frac{ opposite }{hyp }$

5. Nnesha

let NO=x so x is the opposite side of angle 60 and hyp is 24 so substitute $\huge\rm sin(60)= \frac{ x}{24}$ solve for x :=)

6. BeccaB003

So, in a problem like this, whenever you have the information of one angle and one side you always use sin?

7. Nnesha

nope it depends on sides and angles like which angle and side they gave you

8. Nnesha

for this problem we have to apply sin bec like i said earlier we need one angle and one side so given is hyp and angle and we need to find NO which is opposite side of angle that's why sin

9. BeccaB003

So, sin 60 = .866 * 24 = 20.785

10. Nnesha

mod should be on degree!!

11. Nnesha

e*

12. xapproachesinfinity

sin60=root3/2 no need to write before simplifying

13. Nnesha

yes that's right

14. xapproachesinfinity

i meant no decimal before simplifying :)

15. BeccaB003

My calculator is on degree. I checked. Also, I need to know How to know whether a problem is sin cos or tan?? I want to be able to know right off from looking at the problem which one I need to use.

16. Nnesha

well if you have 3 variables formula you should know values of 2 variables to find 3rd one |dw:1434509817378:dw| i need opposite side and given is hyp so i should apply sin which is equal to opposite over hyp

17. BeccaB003

Also, my answer option isn't 20.785 These are the only options I have and they don't make sense when I do the problem: $12\sqrt{2}$ 12 $12\sqrt{3}$ $24\sqrt{3}$

18. xapproachesinfinity

it is just convenient that you write roots as they are

19. xapproachesinfinity

you see if the answer were written in that form, no decimal no calculator is needed!

20. Nnesha

okay then :D

21. Nnesha

it depends on answer choices :=)

22. xapproachesinfinity

not really most often radical need to be written as they if we cannot simplify them

23. xapproachesinfinity

as they are*

24. BeccaB003

I'm confused. I did the problem but it isn't one of the options.... can you convert it??

25. xapproachesinfinity

that is why i'm saying that lol you see sin60=x/24 ===> x=24sin60=24 root(3)/2=12root(3)

26. Nnesha

yes otherwise they should know the unit circle pattrn or at least memorize it

27. xapproachesinfinity

28. xapproachesinfinity

yeah must have the unit circle :)

29. BeccaB003

Also, @Nnesha thank you for your example about recognizing sin, cos, and tan. After I've completed the current problem, can you draw another example like you did and see if I can recognize the correct one; sin, cos, or tan?

30. BeccaB003

Thank you! @xapproachesinfinity

31. xapproachesinfinity

no problem

32. Nnesha

they are not allowed to have unit circle 'n the final exam :=)

33. Nnesha

:3

34. xapproachesinfinity

i meant they need to know some way or the other not taking it in the exams hahaha

35. xapproachesinfinity

i actually memorized them from table lol but if i forgot any one of them i use special triangles

36. BeccaB003

haha! oh bother..... my exam is gonna be fun. I never learned about a 'unit circle' in my class.....

37. Nnesha

^^^^see

38. Nnesha

$$\color{blue}{\text{Originally Posted by}}$$ @xapproachesinfinity i actually memorized them from table lol but if i forgot any one of them i use special triangles $$\color{blue}{\text{End of Quote}}$$ same i memorized it 2 no time for 45-45-9- and 30-60-90 theorem :D

39. Nnesha

oh forgot about that okay give me a sec

40. Nnesha

|dw:1434511171692:dw| find angle B :=_

41. Nnesha

|dw:1434511566103:dw| or this one :=)