A thin \(0.15-\mathrm{kg}\) rectangular sheet has \(40-\mathrm{mm}\) short sides and \(80-\mathrm{mm}\) long sides. Determine the rotational inertia of the sheet about an axis perpendicular to it and located \((a)\) at the center of a long side, \((b)\) at the center of a short side, and \((c)\) at a corner.