Opposite sides and opposite angles in a parallelogram are congruent. $\displaystyle{\overline{{{T}{Q}}}}\usepackage{cmbright}\Huge\$ and $\displaystyle{\overline{{{S}{R}}}}\usepackage{cmbright}\Huge\$ are opposite sides and are congruent. However, because $\displaystyle\angle{R}\usepackage{cmbright}\Huge\$ and $\displaystyle\angle{Q}\usepackage{cmbright}\Huge\$ are adjacent angles in parallelogram RSTQ, they are not necessarily congruent.