Posted by Angela on .
x
________________<20*
<90*
y 
<70*
(hypotenuse length is 12 units)
I'm learning about trig ratios, and my dad was trying to compare it to a circle or something? All I know is
sin = a/c
cos = b/c
tan = a/b
you're trying to figure out the proportions of the lengths of the triangle relative to its angles, actually the other way around in this case.
In accordance with the ratios I listed above,
side A is opposite angle A
side B is opposite angle B
side C is opposite angle C
so, in this case, the right angle is <C and the hypotenuse is side C
thus, does: ?
sin = y/12
cos = x/12
tan = y/x
Now I'm a little confused on how to bring in the angles, and how do I know whether to use sin,cos, or tan?
_______________________________________________
What happens with a problem where I know 2 of the sides, and that it's a right triangle? I then have to figure out the other two angles x and y.
I can figure out the length of the third side using the Pythagorean theorem, but how to I reverse to figure out the angular proportions from the lengths?
Thanks

Geometry 
Reiny,
your Dad is making the connection between the "unit circle" and basic trigonometry.
Do a Google search for "unit circle" or "trigonometry and the unit circle"
You will get many webpages, here is one that seems to be quite good
(Broken Link Removed)