A block of mass 10kg is suspended by three strings as shown in the figure. The tension T₂ is

 

$$\begin{gathered} {\mathrm{T}}_3\sin {60}^{\circ }={\mathrm{T}}_2\sin {30}^{\circ } \\ \therefore {\mathrm{T}}_3 = \frac{{\mathrm{T}}_2}{\sqrt{3}} \end{gathered}$$

Now, $$\begin{gathered} {\mathrm{T}}_2 \cos {30}^{\circ }+ {\mathrm{T}}_3 \cos {60}^{\circ }= {\mathrm{T}}_1 = 100 \\ \mathrm{or} \frac{\sqrt{3} {\mathrm{T}}_2}{12}+\frac{{\mathrm{T}}_2}{\sqrt{3}}\times \frac{1}{2}=100 \\ \mathrm{or} \frac{8{\mathrm{T}}_2}{4\sqrt{3}}=100 \mathrm{or} {\mathrm{T}}_2 = 50\sqrt{3} \mathrm{N} \end{gathered}$$