7-4 Reference Angles!

Merry Christmas! :D I loveee Christmas!! So this weeeek I am going to do my blog on finding referencee angles! This is super easy, so it shouldn't take that longg.

Here are a few steps you need to know:

• First thing you have to do is find the original quadrant and sketch it.
• The next thing you need to do is figure out if the angle is positive or negative. You can use the unit circle the formulas: cos=x/r, sin=y/r, tan=y/x, sec=r/x, csc=r/y.
• The last thing you have to do is either subtract my 360 or 180 until the angle is in between 0 and 90.

So now that you know all that, I am going to work an example!

Example: Find the reference angle of sin 400 degrees.

• First you subtract, which gives you 220. That lets you know that it is in the thrid quadrant.
• It is going to be negative because sin is y and y in the third quadrant is negative.
• Then you subtract 220 from 180 and get 40.
• Your final answer is going to be -sin 40 degrees.

And thats it for this weeeek! Have a happy holidays!

--Halie! :D