Question $2(20$ marks$)$

Determine the centroid of the cross$-$sectional $($shaded$)$ area of the box girder shown in

Figure $2$ with respect to reference axes defined along the left and lower edges of the cross$-$sectional area.

$[$C$4$:CO$2$: PO$2$: WP$1,$ WP$2,$ WP$3][20$ marks$]$

$..\mathrm{.}4/-$

$3$

$4$

Figure $2$