Qu. 4 The strength of a W 14 X 38 rolled steel beam is increased by attaching a 9 x 4 - in. plate to its upper flange as shown. Determine the moment of inertia and the radius of gyration of the composite section with respect to an axis that is parallel to the plate and passes through the centroid C of the section. 9 in. 34 ¾ in. C- 14.1 in. 6.77 in.