Solving Physics Homework: Tension in Bow String at 30.0lb Force

[rock_star]

Homework Statement

Pulling the string on a bow back with a force of 30.0lb , an archer prepares to shoot an arrow.

If the archer pulls in the center of the string, and the angle between the two halves is 126 degrees, what is the tension in the string?



2. The attempt at a solution

cos (126/2) = 30/T
T=29.5

This answer is wrong. I don't know where I messed up. I even got 66 and 60 once during trying to solve this. All of them were wrong.

Can anyone please help me out?

 

[rock.freak667]

If you draw the vectors for the two tensions, you should get two vector components in the direction opposite to the 30lb pulling force.

 

[rock_star]

If you draw the vectors for the two tensions, you should get two vector components in the direction opposite to the 30lb pulling force.

I tried something like this
2Tcos(126/2) =30
T = 33.07
is it close enough?

Thanks a lot!