The angle that is congruent to angle 1 is angle 4 (m∠ 4).
What is congruent angle?
Congruent angles are angles that have the same measure in degrees or radians. So, if two angles are congruent, it means that they are equal in size.
From the diagram of the parallel lines, the angle that is all congruent to angle 1 include;
m∠ 1 = m∠ 4 (vertically opposite angles are equal)
m∠ 2 = m∠ 5 (vertically opposite angles)
m∠ 3 = m∠ 6 (vertically opposite angles)
So m∠ 1 = m∠ 4
Thus, the angle that is congruent to angle 1 is angle 4.