Rotational Inertia-

Particle 1: m=50g x=2 cm y=2 cm
P 2: m=25 x=0 y=4
P 3: m=25 x=-3 y=-3
P 4: m=30 x=-e y=4

The question says to find the rotational inertia of the collection about the x, y, and 7 axis in g/cm^2, then suppose the x axis rotational inertia is A and the y axis is B, then what is the z axis in terms of A and B?

I'm so confused on rotational inertia I don't even know where to begin

Any help would be much appreciated