$(3.)$ An angled member $(AB)$ is attached to a wall by a pin joint at point A and loaded as shown. It is supported by member $BC,$ an aluminum square bar $({0\mathrm{.}25}^{\text{'}\text{'}}{0\mathrm{.}25}^{\text{'}\text{'}}),$ in tension. Determine the unknown reaction forces $($Ib$),$ the stress $($psi$)$ in member $BC,$ the total elongation $($in$)$ of member BC$.$ psi$)$

$$