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## anonymous one year ago I'm so frustrated on this problem! Please help! This is my first time on open study, please help! In △PQR, find the measure of ∡P.

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1. anonymous

2. anonymous

Can anyone see the picture I posted for the problem.

3. imqwerty

Can u find out tan of angle P

4. phi

this is trig. If you need a quick refresher, see https://www.khanacademy.org/math/geometry/right_triangles_topic/cc-geometry-trig/v/basic-trigonometry

5. anonymous

I do know that the tan function is opposite over adjacent. So then that'd put 33.8/57.6

6. imqwerty

Yes can u calculate its value

7. phi

yes. now use a calculator

8. anonymous

Don't you divide 33.8 into 57.6 and get 0.5868, but then you'd need to use something else which then confuses me.

9. phi

you have tan x = 0.5868... use "inverse tan" or $$\tan^{-1}$$ key on 0.5868...

10. imqwerty

Yes now do uknw the value of tan60degrees

11. imqwerty

Sorry i mean tan(30)

12. anonymous

Would you type in: tan^-1 and then 0.5868?

13. phi

On my calculator, I first type in the number then hit shift (or inverse) then tan (marked $$\tan^{-1}$$

14. anonymous

Oh, I forgot to tell you guys the answer choices: A) 30.4 B) 35.9 C) 54.1 D) 59.6

15. phi

it will be obvious if you figure out how to use your calculator.

16. imqwerty

^

17. anonymous

I'm trying to figure it out now. Just a second.

18. anonymous

So, I did like you said, I typed in the number (0.5868) and then I pressed shift and press tan^-1, but it gave me an error?

19. phi

try it the other way

20. anonymous

I did tan^-1 and typed in the numbers as well, and it gave me: 0.5306

21. phi

you are in radian mode. multiply by 180/pi or easier, change your mode to degrees

22. anonymous

How would I change the mode? The calculator I'm using is a Casio. Sorry if I'm making this challenging, I'd just like to understand the problem.

23. phi

what model casio ?

24. anonymous

fx-9750GII

25. phi

I'm looking at the manual. meanwhile, to get the answer, multiply 0.5306*180/pi

26. anonymous

Thank you for you help by the way, so I punched in what you told me to and I got: 30.416

27. phi

which rounds to 30.4º to change mode to "degrees" use shift menu (this gets you to "setup")

28. anonymous

Okay, I did that. Then what?

29. phi

you should see "angle" at the bottom scroll down using the "down cursor"

30. anonymous

Yes, then press Execute?

31. phi

it says press function keys to change the setting?

32. phi

try F1

33. phi

yes, execute, then F1 (I am guessing)

34. anonymous

Okay, I'll try it. Just a moment please.

35. anonymous

Hm, so I pressed execute then F1, it takes me to the Matrix suggestions. They're from A-Z and then after Z is Mat Ans.

36. phi

were you on the "angle" line when you hit exe ?

37. anonymous

Yes, I was.

38. phi

try again, just to be sure

39. anonymous

Okay, I'll tell you what I've been doing. I press the shift button and then press the Menu button but it takes me to the Set Up since that is for the shift button. Then I move downward to "Angle" and next to the word angle on the far right is the words: " :Rad" I then press Execute and go to F1, not using the shift bar or anything else.

40. phi

maybe once you are at the angle line, just press F1 ?

41. anonymous

It doesn't take me anywhere.

42. phi

does rad change to deg ?

43. anonymous

Oh, yes it does. Once I pressed F1 it changed to Deg.

44. phi

now use exit button

45. anonymous

Okay, then what next?

46. phi

check it works, try shift tan ( $$\tan^{-1}$$ ) 0.5868

47. anonymous

I typed in exactly what you told me to and I got: 30.4. So yes, it worked! I'm so happy. Thank you for helping me through this problem and fixing my calculator haha. You've been a great help!

48. phi

so what you did was tan x = 0.5868 then you did "inverse tan" of both sides $\tan^{-1}\left( \tan x\right) = \tan^{-1} 0.5868 \\ x= \tan^{-1} 0.5868 \\ x= 30.4 \ degrees$

49. anonymous

Yes, I understand fully now how I got my answer. Is there any way you could help me on another problem I have?

50. phi

please close this post and make a new one. (this one is a bit long)

51. anonymous

Okay, thank you!

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