$3.$

The shear stress at $A$ in the section shown below is given as $=\frac{VQ}{It}$ where $Q$ is the first moment of the area above point A with respect to the neutral axis. $Q$ can be evaluated as: $Q=bt(\frac{?}{\text{b}\text{a}\text{r}}(y)-\frac{t}{2}).$ Evaluate in ${?}^3{?}^3)$ given $b=9$ in$,t=2\mathrm{.}3$ in$,$ and $d=15$ in$.$ Express your answer using one $(1)$ digit after the decimal point.

$4.$

A rectangular cross$-$section with a width $b=155mm$ and a depth $d=227mm$ is subjected to a shear force $V=84kN.$ What is the maximum shear stress in this cross section? Express your answer in MPA using two $(2)$ digits after the decimal point.