Correct. Because $\displaystyle\angle{J}{K}{L}\usepackage{cmbright}\Huge\$ is a straight angle, its measure is $\displaystyle{{180}}^{\circ}\usepackage{cmbright}\Huge\$ . Therefore:

$\displaystyle{{60}}^{\circ}+{m}\angle{M}{K}{N}+{{35}}^{\circ}={{180}}^{\circ}\usepackage{cmbright}\Huge\$ ,

so $\displaystyle{m}\angle{M}{K}{N}={{180}}^{\circ}-{{60}}^{\circ}-{{35}}^{\circ}={{85}}^{\circ}\usepackage{cmbright}\Huge\$ .