How to calculate the extension of a spring?

[abruzzi112]

I usually have problems regarding Hooke's law and stuff. Please help me with the question below.. I came across it when I was doing my revision.
An explanation will be appreciated.
Thanks!

 

[jbriggs444]

This is homework-like. What have you tried?

The problem states that the springs are identical. It may help to pick an arbitrary spring constant and call it k. What is the effect of extending the first two springs by a distance x?

It may also help to recall that the sine of 30 degrees is 0.5