I'm having some trouble with the following question:

Obviously I know to use Hooke's equation somewhere in this problem: [itex]F = -kx[/itex]

In the above equation, F = the force, caused by gravity, of the board pulling the spring horizontally, and k = 176 N/m as given. So, I need to find x, the length at which the spring is stretched.

What I'm having trouble with is finding the component of the gravitational force that is pulling the spring horizontally. My first instinct told me to try [itex]mg cos(50.0^o)[/itex], but I can see now that that's very wrong.

The answer in the back of the book is 0.236 m, but I can't seem to get that no matter what I do. Could anyone help?