Chapter 7 - Exponents and Exponential Functions - 7-8 Geometric Sequences - Practice and Problem-Solving Exercises - Page 470: 12

The common ratio is $1/3$

You have the sequence:162, 54, 18, 6.find the common ratio by using the formula: R=$\frac{a2}{a1}$,R=$\frac{a4}{a3}$.Plug in the values to get the ratios r=$\frac{54}{162}$=$\frac{1}{3}$ r=$\frac{6}{18}$=$\frac{1}{3}$ There is a common ratio, r=$\frac{1}{3}$. So the sequence is geometric.