As shown, a truss is loaded by the forces P$1=2\mathrm{.}21$ kN and P$2=0\mathrm{.}910$ kN and has the dimension a $=$

$3\mathrm{.}10$ m

a$)$ Determine FBC$,$ the magnitude of the force in member BC$,$ using the method of joints.

b$)$ Determine FCG and FGH$,$ the magnitudes of the forces in members CG and GH$,$ respectively using

the method of joints.