#### Answer

The sequence is geometric.
The common ratio is $r=2$.

#### Work Step by Step

A geometric sequence has a common ratio $r$. The common ratio is multiplied to the current term to get the next term of the sequence.
The common ratio is equal to the the quotient of a term and the term before it.
Solve for the ratio of each pair of consecutive terms to obtain:
$\dfrac{6}{3} = 2
\\\dfrac{12}{6}=2
\\\dfrac{24}{12} = 2$
Since the ratio is common to all pairs f consecutive terms, then the sequence is geometric.
The common ratio is $r=2$