All of your questions rely on TWO things.
a) the field around a single long straight wire is ki = Br
b) the direction of the field is circular around that wire given by your right hand rule.
So for each wire find the distance from the point, the magnitude of the magnetic field caused by that wire then add them ( as vectors ) to get the resultant field.
You have asked four almost identical questions and they are all solved using this method above.