a$)$ Divide the $30kN$ force acting on the point $(2\mathrm{.}2)$ in the

figure into $F_1,F_2$ and $F_3$ components in the I$-$I, II$-$II

and III$-$III directions.

b$)$ Balance the resultant force with two forces passing

through the I$-$I and II$-$II directions.