Three conductors of same length having thermal conductivity k_1,...

Three conductors of same length having thermal conductivity $\mathrm{k}_1, \mathrm{k}_2$ and $\mathrm{k}_3$ are connected as shown in figure.
Area of cross sections of $1^{\text{st }}$ and $2^{\text{nd }}$ conductor are same and for $3^{\text{rd }}$ conductor it is double of the $1^{\text{st }}$ conductor. The temperatures are given in the figure. In steady state condition, the value of $\theta$ is _______ ${ }^{\circ} \mathrm{C}$. (Given : $\mathrm{k}_1=60 \mathrm{Js}^{-1} \mathrm{~m}^{-1} \mathrm{~K}^{-1}, \mathrm{k}_2=120 \mathrm{Js}^{-1} \mathrm{~m}^{-1} \mathrm{~K}^{-1}, \mathrm{k}_3=135 \mathrm{Js}^{-1} \mathrm{~m}^{-1} \mathrm{~K}^{-1}$ )