Torque on a small loop by a large loop?

[zyphriss2]

A small loop of wire of radius 2.0 cm is placed at the center of a wire loop with radius 24 cm. The planes of the loops are perpendicular to each other, and a 6.0 -A current flows in each. Estimate the magnitude of the torque the large loop exerts on the smaller one.

I know the rules but I honestly have no Idea on where to start.

 

[Doc Al]

Start by figuring out the magnetic field at the center of the large loop.