Let's draw a picture and see:
find the trig functions of angle if the terminal side of passes through the point (-12, 5).
Notice I changed the name of the angle from x to because
x stands for the first coordinate of a point. If you use x to refer
to the angle too, you will have a conflict of variables. That's a
no-no.
Now we draw a perpendicular line down to the x-axis:
Next we cut off the green line beyond the right triangle, and label
it r. We use the Pythagorean theorem to calculate r:
Edwin