Shown on the right, is a rigid structure ABCDEFG $($fixed at

joint A and D$)$ supports $15$kN load. The member EFG is

held in place by rigid sticks AB$,$ BC$,$ CG$,$ AE$,$ BF$,$ CF$,$ and

DE$.$ All rigid sticks and EFG are connected at each joint.

$(1)$ Determine the force in member AE