Determine the rod forces $S1,S2,$ and $S3$ to balance the external forces $($action$)P1,P2,$ and $R$ in:

$($a$)$ Graphical way to determine

$($b$)$ Analytical way to determine

Hint: the answer is

$S1=69\mathrm{.}28kN($to the left leaving the gusset point$)$

$S2=-52\mathrm{.}9kN($to the top towards the gusset point$)$

$S3=-40kN($to the bottom towards the gusset point$)$