The drawing below shows the bean $($B$)$ and girder $($G$)$ layout for a small one$-$

story office building. If $D=8ft$ and $L=30ft,$ what is the tributary area for

girder G$-1?$

$240f{t}^2$

Can not be determied with knowing the loads $($LL$,$ DL$)$

$480f{t}^2$

$720f{t}^2$

$360f{t}^2$