\(\,{\text{x}}\,\, = \,\,\frac{{\sqrt {{\text{10}}\,\, \times \,\,{\text{1}}{{\text{0}}^{{\text{ - 3}}}}} }}{{\sqrt {10\,\, \times \,\,{{10}^{ - 3}}\,\,} \,\, + \,\,\sqrt {20\,\, \times \,\,{{10}^{ - 3}}} }}\,\, \times \,\,80\)
\(x\,\, = \,\,\frac{{{{10}^{ - 1}}}}{{{{10}^{ - 1}}\,\, + \,\,\sqrt 2 \,\, \times \,\,{{10}^{ - 1}}}}\,\, \times \,\,80\,\, = \,\,33\,cm\)
[${\varepsilon _0} = 8.85 \times {10^{ - 12}}\,{C^2}/N - {m^2},{R_E} = 6.37 \times {10^6}\,m$]