If the sin 30° is 1 over 2, then the cos ____° = _____.

60° ; 1 over 2
30° ; square root 2 over 2
60° ; square root 3 over 2
30° ; 1

Question

If the sin 30° is 1 over 2, then the cos ____° = _____. 

 60° ; 1 over 2 
 30° ; square root 2 over 2 
 60° ; square root 3 over 2 
 30° ; 1

anonymous · Answer

I will give a medal please help

anonymous · Answer

sin is opp/hyp
cos is adj/hyp

whpalmer4 · Answer

Sin and Cos are complementary: Sin(x) = Cos(90-x) and Cos(x) = Sin(90-x)

whpalmer4 · Answer

(where working in degrees, that is)

anonymous · Answer

would it be c

anonymous · Answer

opp = 1
adj = 2
hyp =

anonymous · Answer

but u said sin is opp over hyp so the opp would be 1 and the hyp would be 2

whpalmer4 · Answer

|dw:1394493698023:dw|

anonymous · Answer

so it would be c right?

anonymous · Answer

yes I made a typo - you are right!

whpalmer4 · Answer

|dw:1394493798245:dw|

No.  $$\sin(x) = \cos(90^\circ - x)$$

whpalmer4 · Answer

If $x = 30^\circ$, then $$\sin(30^\circ) = \cos(90^\circ-30^\circ) = \cos(60^\circ)$$

anonymous · Answer

but it would have to be 60 degrees and the other one with 60 degrees doesn't make sense

whpalmer4 · Answer

The picture is symmetrical.  The second one I drew shows the line for 60 degrees, and there the hypotenuse is 1 (because this is the unit circle), the adjacent side will be 1/2, and the opposite side will be sqrt(3)/2.  Earlier, when the angle was 30 degrees, we had the hypotenuse = 1, the opposite side = 1/2 and the adjacent side = sqrt(3)/2.

anonymous · Answer

oh ok thank you

anonymous · Answer

60° ; 1 over 2 , because the angles are complementary
i just took this test and got this wrong, the is the right answer