In statics, a structure is statically indeterminate (or hyperstatic) when the static equilibrium equations are insufficient for determining the internal forces and reactions on that structure.
Static Indeterminacy :-
When the number of unknown forces is more than the number of equilibrium equations required to find the forces, then the system is said to be statically indeterminate;
N1 = Number of unknown forces,
N2 = Number of equilibrium equations to be solved;
Then, “Q” is called the Degree of (Static) Indeterminacy,
where, “Q” is defined as follows;
Q = N1-N2