Question

Find the common ratio, r, in the following geometric sequence. 27, 9, 3, 1,…

Answer 1

The common ratio is 1/3
27/3 = 9
9/3 =3
3/3=1

Answer 2

To find the common ratio 
divide by the previous numb/number beside it:
 $\frac{9}{27}=\frac{1}{3},\:\quad \frac{3}{9}=\frac{1}{3},\:\quad \frac{1}{3}=\frac{1}{3}$


so $r=\frac{1}{3}$