Answer
$12288$
Work Step by Step
First, we must determine the common ratio between the terms:
$r=\frac{12}{3}=\frac{48}{12}=\frac{192}{48}=4$
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.
$a_{7}=3 \times (4)^{7-1}=12288$
