Answer:

1. 2, 6, 18, 54, 162, 486

Rule: times 3

2. 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128

Rule: times 2

3. 1, 4, 16, 64, 256, 1024

Rule: times 4

4. 3, 9, 27, 81, 243, 729

Rule: times 3

How to get the common ratio?

(1. 2, 6, 18, 54, 162, 486)

Divide the second term to the first term (6÷2=3)

Therefore, to get the next sequence, do this way.

2 is the first term, so...

2×3= 6 (The second term)

6×3= 18 (Third term)

18×3= 54 (Fourth term)

54×3= 162 (Fifth term)

162×3= 486 (The sixth or the last term)

1. 2, 6, 18, 54, 162, 486