Correct. The acute angles are complementary, so $\displaystyle{m}\angle{K}={{45}}^{\circ}\usepackage{cmbright}\Huge\$ . This is a $\displaystyle{{45}}^{\circ}-{{45}}^{\circ}-{{90}}^{\circ}\usepackage{cmbright}\Huge\$ triangle. One way to find the length of $\displaystyle{\overline{{{J}{L}}}}\usepackage{cmbright}\Huge\$ is to use the fact that the length of the hypotenuse is $\displaystyle\sqrt{{2}}\usepackage{cmbright}\Huge\$ times the length of the leg:

$\displaystyle\sqrt{{2}}\cdot{k}={3}\sqrt{{2}}\Rightarrow{k}={3}\usepackage{cmbright}\Huge\$

In a $\displaystyle{{45}}^{\circ}-{{45}}^{\circ}-{{90}}^{\circ}\usepackage{cmbright}\Huge\$ triangle, the length of the two legs are equal, so $\displaystyle{j}={3}\usepackage{cmbright}\Huge\$ .