Angle 2 is congruent to angle 5 because they are vertical angles. Angle 5 is congruent to angle 9 because they are same-side interior angles. Angle 9 is congruent to angle 14 because they are vertical angles. Lastly, angle 14 is congruent to angle 15 because they are same-side interior angles. Therefore, angle 2 is congruent to angle 15.