Four long, straight wires parallel to the z axis pass through the points (±7.5 cm, ±7.5 cm) at the corners of a square in the x-y plane. Each carries a current of 2.5 A, with the upper two currents in the -z direction and the lower two in the +z direction. Find the magnetic field at the center of the square.
The Attempt at a Solution
Defining out of the page as the positive z-axis:
Using the right hand rule, the magnetic field will point to the left.
I don't really know how to find the magnitude, though. Do I treat each as a line current and add them together?