Answer
Geometric, the ratio is $\frac{1}{3}$
Work Step by Step
You have the sequence:81,27,9,3. 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=$\frac{27}{81}$=$\frac{1}{3}$
r=$\frac{3}{9}$=$\frac{1}{3}$
There is a common ratio,r=$\frac{1}{3}$. So the sequence is geometric.
