The strength of the wide flanged rolled section shown is increased by welding a channel to its upper flange.
Determine the moment of inertia and radius of gyration of the combined section with respect to its centroidal $x$ and $y$ axes.
$\bar{y} = 27 \text{ mm}$
$\bar{I}_{x’} = 745 \times 10^6 \text{ mm}^4$
$\bar{I}_{y} = 91.4 \times 10^6 \text{ mm}^4$
