To determine the common ratio of a geometric sequence, you divide any term by the previous term. Let's calculate the common ratio using the first two terms:
- First term: \(2\)
- Second term: \(12\)
The common ratio \(r\) is given by:
\[
r = \frac{\text{second term}}{\text{first term}} = \frac{12}{2} = 6
\]
Now let's check if this ratio holds for the next pair of terms:
- Third term: \(18\)
Calculating the ratio between the second and third terms:
\[
r = \frac{18}{12} = 1.5
\]
This shows that the sequence is not geometric because the ratios are not the same.
Let's check the ratio for the third and fourth terms:
- Fourth term: \(132\)
Calculating the ratio between the third and fourth terms:
\[
r = \frac{132}{18} = \frac{132 \div 6}{18 \div 6} = \frac{22}{3} \approx 7.33
\]
The ratios are all different, indicating that this sequence is not a geometric sequence at all. Therefore, there isn't a common ratio.
Based on the options provided (12, \( \frac{1}{2} \), \( \frac{1}{4} \), 4, -1.5), none of these is the correct common ratio, as there is no common ratio due to the inconsistency in the ratios.
If you need further assistance, please clarify if there are more terms or if adjustments can be made to your query.