Question

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

3


-3


1/3


-9

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:

`(9)/(27)=(1)/(3),\:\quad (3)/(9)=(1)/(3),\:\quad (1)/(3)=(1)/(3)`


so
`r=(1)/(3)`