Problem $3(10$ points$)$:$($Don$\text{'}$t need to calculate$)$

Consider the statically indeterminate truss in the figure, which is subjected to horizontal force at joint D of P $.$

$($a$)$ Determine the degree of indeterminacy and whether the truss is internally or externally statically indeterminate $($show your work$).$

$($b$)$ Illustrate the Force Method procedure to solve the truss due to the applied load by showing $($Note$,$ do not have to calculate. Just concepts check$).$

Propose a statically determinate structure

Illustrate the Superposition

Write down the Compatibility equation based on your superposition

Illustrate the principle of virtual work concepts for solving the displacements in the compatibility equation