Finding Common Ratios

Divide each term by the previous term to determine whether a common ratio exists.

1. ⓐ $\begin{array}{llllllllll}\frac{2}{1}=2\hfill & \hfill & \hfill & \frac{4}{2}=2\hfill & \hfill & \hfill & \frac{8}{4}=2\hfill & \hfill & \hfill & \frac{16}{8}=2\hfill \end{array}$

   The sequence is geometric because there is a common ratio. The common ratio is 2.

2. ⓑ $\begin{array}{lllllll}\frac{12}{48}=\frac{1}{4}\hfill & \hfill & \hfill & \frac{4}{12}=\frac{1}{3}\hfill & \hfill & \hfill & \frac{2}{4}=\frac{1}{2}\hfill \end{array}$

   The sequence is not geometric because there is not a common ratio.