Forces and equilibrium — practice question

Three light inextensible strings each have a particle fixed to one end. Their remaining ends are joined at a point $O$. Two of the strings go over fixed smooth pegs, and the particles are suspended freely in equilibrium. The weights of the particles together with the angles between the sloping sections of the strings and the vertical are indicated in the diagram. It is given that $\sin \beta = 0.8$ and $\cos \beta = 0.6$.