Question

The uniform solid block in Fig. 11-36 has a mass of M = 5.60 kg and edge lengths a = 17.5 cm, b = 39.5 cm, and c = 2.85 cm. Calculate its rotational inertia about an axis through one corner and perpendicular to the large faces

I know you have to find the center of mass to get radius to take cross product and find torque..
but how do i find the "rotational Inertia"