There are 2 pairs of vertical angles and they are:
angle NOP and angle ROS
angle POR and angle NOS
To see this, it might help to use a different color to mark the segments NR and SP. A giant X forms. The angles NOP and ROS are opposite one another, so they are vertical angles.
Similarly, angles POR and NOS are opposite one another so they are the second pair of vertical angles.
Vertical angles are congruent, meaning that angle NOP = angle ROS. Also, angle POR = angle NOS
No other vertical angle pairs are present because the segments MO and QO do not extend past point O.
