As shown in Fig. B6, three long wires are perpendicular to the page, and each carries a current of 3 A flowing out of the page. They form an equilateral triangle with sides of 0.2 m. A fourth wire (wire b) passes through the midpoint of the base of the triangle and is parallel to the other three wires. If the net magnetic force on wire a is zero, determine the the magnitude and direction (out of the page or into the page) of the current in wire b.
