Posted by **Anonymous** on Saturday, March 10, 2007 at 12:03am.

On a piece of paper draw and label a right triangle using the given sides, solve for the unknown side and write the trigonometric functions for angles A and B, if a=5 and c=7.

I already found side b which equals 2 sqrts of 6.

Now I need to find the sin A and cos A. I know that sin is opposite/hypotenuse and cos is adjacent / hypotenuse. Thatâ€™s as far as I can get however, I am provided with choices;

Sin A

a)7/5

b)2sqrt6/7

c)7/2sqrt6

d)5/7

Cos A

a)7/5

b)7/2sqrt6

c)2sqrt6/7

d)5/7

Please help!!!

So why not use for sine the value of a/c, and for cosine, b/c ?