If ${\mathrm{x}}_1, {\mathrm{x}}_2, {\mathrm{x}}_3 \dots \dots {\mathrm{x}}_{34}$ are numbers such that ${\mathrm{x}}_{\mathrm{i}}={\mathrm{x}}_{\mathrm{i}+1}=150, \mathrm{\forall }\mathrm{i}\in \{1,2,3\dots ..9\}$ and ${\mathrm{x}}_{\mathrm{i}+1}-{\mathrm{x}}_{\mathrm{i}}=-2\mathrm{\forall }\mathrm{i}\in \{10,11,\dots ..33\}$ and if median of ${\mathrm{x}}_1, {\mathrm{x}}_{2 }\dots \dots {\mathrm{x}}_{34}\text{ is }\mathrm{\lambda }$ then $\sqrt{\mathrm{\lambda }+9}=\mathrm{\_\_\_}$