determine the reference angle 0' for the given angle 0=195 or 120

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- May 18th 2006, 02:52 PM #1

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- May 18th 2006, 05:37 PM #2Originally Posted by
**melissa**

So. 195 degrees is in the third quadrant, just under the -x axis. The reference angle is thus 195 - 180 = 15 degrees.

120 degrees is in the second quadrant. So the reference angle is 180 - 120 = 60 degrees.

Two last examples:

42 degrees. If an angle is in the first quadrant, the angle is its own reference angle, so the reference angle here is 42 degrees. (If you like, the angle is above the +x axis, so 42 - 0 = 42 degrees.)

315 degrees. This is a fourth quadrant angle, so it is below the +x axis. Thus 360 - 315 = 45 degrees is the reference angle.

-Dan

- May 18th 2006, 06:48 PM #3

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