Answer
2.2619
Work Step by Step
If $a\gt0$, $a\ne1$, $b\ne1$, and $x\gt0$, then we know that $log_{a}x=\frac{log_{b}x}{log_{b}a}$.
Therefore, $log_{3}12=\frac{log_{10}12}{log_{10}3}\approx\frac{1.0792}{0.4771}\approx2.2619$.
Recall that $b$ can be any positive number other than 1.