Virtual work in a pulley system

[new90]

Homework Statement

The system is in static equilibrium.Use the principle of virtual to find the weights of A and B.Neglect the weight of the strings and the friction of the pulley

Relevant Equations

no equation

If 1kg make a displacement of 1unit upward then A make a 1/2unit down because 1/sin 30.after that i have no idea what do I will really need help.
Thanks!

 

[Lnewqban]

In order for 1 Kg mass to move, an additional force would need to be applied on it and the geometry would change.

 

[new90]

ok thanks I already solve it