Answer
$0.1875$
Work Step by Step
First, we must determine the common ratio between the terms:
$r=\frac{6}{12}=\frac{3}{6}=\frac{(\frac{3}{2})}{3}=\frac{1}{2}$
For solving this, we will use the formula for the $nth$ term of the geometric series. $a_{n}=a_{1}\times r^{n-1}$. Then put correct value for $7th$ term to solve.
$a_{7}=12 \times (\frac{1}{2})^{7-1}=0.1875$