# Math Help - Complement and supplement of an angle

1. ## Complement and supplement of an angle

Can -7PI/6 (-210 degrees) have a complement and supplement.

Complement no because it has to be a positive degree.

Supplement if I add 30 degrees to -210 it becomes 180 is this possible?

It says that it has to be two positive angles whose sum is 180 degrees. So I think it can since the positive angle of -210 is 150 degrees.

Find a co-terminal angle in the same format
my angle is 3.8 radians

How can I find a co-terminal angle? would I add/subtract 6.283185307? I know I add 2pi if it was pi/4 or 360 degrees if it said 30 degrees.

Thanks

2. A single angle can be given many different measures, all of which can be reduced to one angle between 0 and $\pi$. First remember that we can always add or subtract $2\pi$ since that is just going around the complete circle once, getting back to the same angle. Because the angle given has a denominator of "6", note that $2\pi= 12\pi/6$

$\frac{-7\pi}{6}+ 12\pi/6= 5\pi/6$ which is between 0 and $\pi$. What is the supplement of that? Does it have a complement?

Since the angle is given in radians, as a multiple of $\pi$, you should do the problem that way. You should not have to convert to degrees. That takes time and does not contribute anything. Also, your angle is NOT "3.8 radians", it is $-7\pi/6$ radians, which is [b]approximately[/tex] -3.7 radians. You should not have to approximate.