Moment of inertia of an I-beam with two different flange widths about the beam's centroidal axis As shown, an I-beam has a bottom flange that is150mm x30mm , a web that is 30mm x 150mm, and top flange 75mm x 30mm that is . Determine the moment of inertia of the I-beam about the horizontal centroidal axis using the parallel-axis theorem.