What must be true if a number c is a square root of a non negative number b?

If a number ( c ) is a square root of a non-negative number ( b ), it must be true that ( c^2 = b ) and ( c ) is greater than or equal to zero (i.e., ( c \geq 0 )). This means that ( b ) is either zero or a positive number, as square roots are defined only for non-negative values in the real number system.