An arched roof truss is loaded as shown in the figure.

a$)$ Calculate the support forces by drawing the free body diagram of the truss structure.

b$)$ Calculate the forces in the FH$,$ GH and GI elements using the section method and indicate whether each element is subjected to tension or compression.

c$)$ Calculate the force in the element using the knot method and indicate whether it is subjected to tension or compression.