Problem $3$:

Beam AC is in equilibrium with loading $100$ N at B shown in the figure when $=45.$ Determine the unknown forces Ax and Ay at A in x and y direction and Rc perpendicular to the beam AC in $y^{\text{'}}$ direction at C by using the equilibrium equations: ${\displaystyle \underset{i=1}{\overset{n}{}}}{F}_{ix}=0$;${\displaystyle \underset{i=1}{\overset{n}{}}}{F}_{iy}=0$; and ${\displaystyle \underset{i=1}{\overset{n}{}}}{M}_{oi}=0$ where o is an arbitrary point. $($You have three equations to solve three unknowns.$)$

Please solve with some explanation on how you summed the moments.