1. The 10th term of the geometric sequence 2, 6, 18, 54, 162, ... is 39,366. The common ratio is 3. 2. The common ratio of a geometric sequence with a first term of -1 and a fourth term of -8 is 2. 3. The common ratio of a geometric sequence with a first term of -5 and a fifth term of -80 is 2.