roblem $4$: A rectangular box beam has the section properties given. Compute the maximum TENSILE stress in the box and state where it occurs $($point A$,$ B$,$ or D$).$

Box beam

Section Properties

$I_x=6,900,000m{m}^4$

$I_y=2,900,000m{m}^4$

$A=3,600m{m}^2$