We use dimensional analysis as well as the parallel axis theorem to obtain the moment of inertia for some homogeneous two-dimensional objects. These objects should possess some sort of symmetry: they should have shapes that can be decomposed into smaller copies of themselves. In the second part of the article, it is seen that as the moment of inertia of a composed object is the summation of the moment of inertia of its decomposed parts, this may give us a shortcut to obtaining the moment of inertia of some objects.