Homework Help: Converting radians to degrees, help!

1. Dec 14, 2003

StarkyDee

I know this is an easy problem, but I need to know 3 sets of polar coordinates for the Cartesian coordinates (-4,4$\sqrt{3}}$)

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

How do I convert 4$\sqrt{3}}$) to degrees?

(4$\sqrt{3}}$) = 6.92820 Is this in radians?

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

thanks.

2. Dec 14, 2003

Hurkyl

Staff Emeritus
$4 \sqrt{3}$ isn't an angle...

3. Dec 14, 2003

chroot

Staff Emeritus
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

4. Dec 14, 2003

StarkyDee

Ah. Inverse Tan of y/x.

4$\sqrt{3}}$/-4 = -1.7320 = -60 degrees.

Thanks ~Dave~

5. Dec 14, 2003

Hurkyl

Staff Emeritus

6. Dec 14, 2003

StarkyDee

well -60 degrees would be in the 4th quadrant.
but when i graph (-4,4$\sqrt{3}}$) 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);
opposite angle (8,120). is this correct?

thanks again!

7. Dec 14, 2003

Hurkyl

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

8. Dec 14, 2003

StarkyDee

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.

9. Dec 14, 2003

Hurkyl

Staff Emeritus
right.

10. Dec 14, 2003

StarkyDee

Thanks for helping me out Hurkyl, appreciated much!
Studying for finals have turned my brain into mush.