Answer
$\approx2.977$
Work Step by Step
The sum of a geometric sequence to the $n$th term can be obtained by the formula $S_n=a_1(\frac{1-r^n}{1-r})$ where $a_1$ is the first term and $r$ is the common ratio.
Hence here the sum is: $S_{12}=1(\frac{1-(\frac{2}{3})^{12}}{1-(\frac{2}{3})})=\frac{527345}{177147}\approx2.977$
