Answer
$\tan(B)=\frac{3}{4}$
Work Step by Step
The tangent of an angle in a right triangle is the ratio of the opposite side to the adjacent side. The side opposite to $B$ has a measure of $6$, and the side adjacent to $B$ has a measure of $8$. When we write these in a ratio, we get $\frac{6}{8}$, which simplifies to $\frac{3}{4}$.