A kitchen scale has a structure like the one in the picture. When you put items on the weighing plate, the spring will extend its length, and one can correlate the extension of the spring to the weight of the item. The spring constant k is $1\mathrm{.}2$ kN$/$m

If the spring has been stretched for $3$ cm after we place an item, and the system is at equilibrium condition, determine the force in each of the three cables $($AB$,$ AC$,$ AD$).$