A sequence of the form \left\{t_{1}, t_{2}, \ldots, t_{n}\right\} is called geometric if t_{1}=a, t_{2}=a r, t_{3}= a r^{2}, \ldots, t_{n}=a r^{n-1}. For example, \{1,2,4,8,16\} and \{1,-3,9,-27\} are both geometric sequences. In all three questions below, suppose \left\{t_{1}, t_{2}, t_{3}, t_{4}, t_{5}\right\} is a geometric sequence of real numbers.
(a) If t_{1}=3 and t_{2}=6, determine the value of t_{5}.
(b) If t_{2}=2 and t_{4}=8, determine all possible values of t_{5}.
(c) If t_{1}=32 and t_{5}=2, determine all possible values of t_{4}.