$3.$ The closed thin$-$walled section shown in Fig. $3$ is symmetric about the $\backslash ($ y $\backslash )-$axis.

$($a$)$ Locate the centroid. Use stringer $3$ as the datum.

$($b$)$ Calculate $\backslash ($ I$\_\{$y$\}\backslash ).$

$($c$)$ Find the shear center assuming a cut between stringers $1$ and $2.$

Fig. $3$