In right triangle $LMN$, angle $M$ is a right angle, the measure of angle $N$ is $28^{\circ }$, and the length of $\overline{MN}$ is 30 units. If the area, in square units, of triangle $LMN$ can be represented by the expression $k\tan 28^{\circ }$, where $k$ is a constant, what is the value of $k$?