SOMEONE HELP PLEASE!! Will make as brainleist!??

Answer:
This is a geometric sequence and the common ratio is equal to ½.
Step-by-step explanation:
For a sequence to be termed to be in arithmetic progression, the difference between consecutive terms are the same and constant.
On the other hand, a sequence is termed to be in geometric progression if the ratio of a term to the term before it is the same as the ratio between the next term to it.
Let's consider the sequence given: 12, 6, 3 . . .
=>Let's try to find the common difference if it would be constant: 6-12 (-6) ≠ 3-6 (-3)
The sequence is not arithmetic.
=>Let's also try to find the ratio of the sequence to see if it is constant:
6/12 (½) = 3/6 (½)
Therefore we can conclude the sequence is geometric because the common ratio (½) is constant.
This is a geometric sequence and the common ratio is equal to ½.