Answer
$NM = 23$
Work Step by Step
The diagram indicates that $\overline{MN}$ bisects both $\overline{JL}$ and $\overline{JK}$. According to the triangle midsegment theorem, if a line segment joins two sides of a triangle at their midpoints, then that line segment is parallel to the third side of that triangle and is half as long as that third side.
Knowing this information, we can deduce that $\overline{LK}$, which is the third side, is parallel to $\overline{NM}$, which is the line segment, and that $LK$ is two times the length of $NM$. We can now set $LK$ as two times the length of $NM$ to find what $NM$ is:
$LK = 2(NM)$
Let's plug in what we know:
$46 = 2(NM)$
Divide each side by $2$ to solve for $NM$:
$NM = 23$
