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Converting radians to degrees, help!

  1. Dec 14, 2003 #1
    I know this is an easy problem, but I need to know 3 sets of polar coordinates for the Cartesian coordinates (-4,4[itex]\sqrt{3}}[/itex])

    So I graphed the points and got the hypotenuse, r = 8.

    How do I convert 4[itex]\sqrt{3}}[/itex]) to degrees?

    (4[itex]\sqrt{3}}[/itex]) = 6.92820 Is this in radians?

    and do I then multiply it by (180/pi) to get degrees?

    thanks.
     
  2. jcsd
  3. Dec 14, 2003 #2

    Hurkyl

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    [itex]4 \sqrt{3}[/itex] isn't an angle...
     
  4. Dec 14, 2003 #3

    chroot

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    It sounds like you've already drawn a triangle -- so use trig to solve for the angle. The angle is the inverse tangent of y/x.

    Why are you trying to convert the cartesian y-coordinate to degrees? That doesn't even make sense.

    - Warren
     
  5. Dec 14, 2003 #4
    Ah. Inverse Tan of y/x.

    4[itex]\sqrt{3}}[/itex]/-4 = -1.7320 = -60 degrees.

    Thanks ~Dave~
     
  6. Dec 14, 2003 #5

    Hurkyl

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    Don't forget to check that your answer is in the correct quadrant!
     
  7. Dec 14, 2003 #6
    well -60 degrees would be in the 4th quadrant.
    but when i graph (-4,4[itex]\sqrt{3}}[/itex]) it is only valid in the 2nd quadrant and you can't have a -60 degrees in the 2nd quad. so if i start in the 4 quadrant at -60

    the 3 points would be: (8,-60);
    add 360 (8,-240);
    opposite angle (8,120). is this correct?

    thanks again!
     
  8. Dec 14, 2003 #7

    Hurkyl

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    Well, tell me, how many of those are in the second quadrant?

    All of your answers must be in the second quadrant because the desired point is in the second quadrant...
     
  9. Dec 14, 2003 #8
    Ah. So -60 would not work because it's in the 4th quadrant. therefore (8,-60) is not a point. that makes sense.

    but (8,-240) and (8,120) and (8,-600) would be in the 2nd quadrant.
     
  10. Dec 14, 2003 #9

    Hurkyl

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    right.
     
  11. Dec 14, 2003 #10
    Thanks for helping me out Hurkyl, appreciated much!
    Studying for finals have turned my brain into mush.
     
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