Two infinetely long, parallel wires are lying on the ground at distance `a=1cm` apart as shown in Fig. A third wire, of length L=10m and mass 400g, carries a current of `I_1=100A` and is levitated above the first two wires, at a horizontal position midway between them. The infinitely long wires carry equal currents `I_1` in the same directions, but in the direction opposite that in the leviated wire. What current must the infinately long wires carry so that the three wires form an equilateral triangle?