The second term in a geometric sequence is 12. The fourth term in the same sequence is 4/3. What is the common ratio in this sequence?

Answer 1

A geometric sequence has the form: a, ar, ar², ar³, ...

So, ar = 12 and ar³ = 4/3

Since ar = 12, a = 12/r.

So, (12/r)r³ = 4/3

12r² = 4/3

r² = 1/9

r = 1/3 or -1/3

Answer 2

____ 36 ____ 4

3 is common.