The Attempt at a Solution
I let µ be 9, as that's the approximate permittivity of air/ free space.
I assumed that as a hat had a subscript y, it ran parallel to the y axis, and worked from there, getting the cross product of the unit vector in the direction of a hat, (which I took to be (0,1,0) ) and (sqrt(1/2), 0, sqrt(1/2)), which I worked out from the x and z positions given, and then scalar multiplying by the preceding stuff.
Did I approach this correctly? If not, where did i go wrong?