Two resistances R₁=X Ω and R₂=1 Ω are connected to a wire AB of uniform resistivity, as shown. The radius of the wire varies linearly along its axis from 0.2 mm at A to 1 mm at B. A galvanometer (G) connected to the center of the wire, 50 cm from each end along its axis, shows zero deflection when A and B are connected to a battery. The value of X is ____.