Use method of joints to solve for the forces. Angle $$ :

$ta{n}^{-1}(\frac{3}{3})=45$

${\displaystyle \underset{?}{\overset{?}{}}}{F}_x=0$

$Ax=0$

$-{\displaystyle \underset{?}{\overset{?}{}}}{F}_y=0$

$Ay-100kN+G_y=0$

$Ay=-50+100$

$Ay=50kN$

${\displaystyle \underset{?}{\overset{?}{}}}{M}_A=0$

$-100(10)+G_y(20)=0$

$G_y=\frac{100(10)}{20}$

$G_y=50kN$