We want to look which angles are congruent to 3 let's analyze the possible options:
Angle 4 is ot congruent since it's not a vertical angle respect to 3
Angle 7 is congruent since 7 and 3 are corresponding angles
Angle 2 is congruent since 2 and 3 are opposite angles
Angle 6 is congruent since 6 and 3 are consecutive interior angles
So