Explain how special right triangles, reference angles, and quadrants of a coordinate grid help us find the exact answer to the following: cos 210°.

Question

ikr2002 · Answer

There were no graphs

snowflake0531 · Answer

Do you know the unit circle?

ikr2002 · Answer

No but I think I'm just trying to explain how to use those methods to find the answer.

snowflake0531 · Answer

fine then

1. Know that cos is the x coordinate
2. tell me which quadrant 210 degrees falls in

ikr2002 · Answer

cos(0) is in Q1?

snowflake0531 · Answer

210 degrees e.e
starting from the coordinate (1,0)

which means that it's in the third quadrant, 30 degrees in
agreed?

ikr2002 · Answer

yeah

snowflake0531 · Answer

so it's like here |dw:1623973191797:dw| the reference angle is 30 degrees

ikr2002 · Answer

so then what about the special right triangles?

snowflake0531 · Answer

|dw:1623973432055:dw| do you see the triangle? fin dx

ikr2002 · Answer

Yeah, so how would I put all of this into words?

snowflake0531 · Answer

draw on it a unit circle, you find out you can draw a right triangle in the third quadrant, then use one of hte trig ratios to find x

ikr2002 · Answer

I can't respond using images just text. So I'm trying to figure out how to describe these features in words. Thank you!

snowflake0531 · Answer

just describe the circle and the angles -- have fun --- and yw~