Consider the geometric sequence: 5, 15, 45, 135, 405, …. What is the common ratio?
To find the common ratio in a geometric sequence, you divide any term in the sequence by the term immediately preceding it.
In this sequence, to find the common ratio, we can choose to divide 15 by 5, or divide 45 by 15, or divide 135 by 45, etc.
Let's divide 15 by 5:
15 / 5 = 3
Therefore, the common ratio in this geometric sequence is 3.