SOLUTION: Hi, if theta is an acute angle and sin theta =1/2, then cos theta= I have drawn a right triangle with the hypotenus on the right. It has a one on the bottom and a two on the hyp

Algebra ->  Triangles -> SOLUTION: Hi, if theta is an acute angle and sin theta =1/2, then cos theta= I have drawn a right triangle with the hypotenus on the right. It has a one on the bottom and a two on the hyp      Log On


   

Question 165593: Hi, if theta is an acute angle and sin theta =1/2, then cos theta=
I have drawn a right triangle with the hypotenus on the right. It has a one on the bottom and a two on the hypotenuse. Then I tried 1^2+b^2=2^2 and ended up with square root of b^2 =square root of 3. I do not know where to go from there

Thankyou.
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You have done ok so far!
In your triangle, you have a+=+1, c+=+2, and b+=+sqrt%283%29.
To see how we get b, you have:
b%5E2+=+3 Take the square root of both sides.
b+=+sqrt%283%29
The sin of theta (I'll call it A because I can't do a theta symbol) is given as 1%2F2 because the sine of the angle is the side opposite the angle (a = 1) over the hypotenuse (c = 2), so you get sin%28A%29+=+1%2F2
The cosine of this angle (A) is the side adjacent to the angle (b+=+sqrt%283%29 over the hypotenuse (c = 2), so...
cosin%28A%29+=+sqrt%283%29%2F2