Because M and S are corresponding angles, the sides opposite them are corresponding. So $\displaystyle{N}{P}\leftrightarrow{T}{R}\usepackage{cmbright}\Huge\$ . Because N and T are corresponding angles, the sides opposite them are corresponding. So $\displaystyle{M}{P}\leftrightarrow{S}{R}\usepackage{cmbright}\Huge\$ . Because two angles have the same measures, the third angles must be congruent. So $\displaystyle\angle{P}\leftrightarrow\angle{R}\usepackage{cmbright}\Huge\$ , and therefore $\displaystyle{M}{N}\leftrightarrow{S}{T}\usepackage{cmbright}\Huge\$ .