Final answer:
The consecutive interior angles theorem states that when two parallel lines, p and q, are cut by a transversal, t, the angles on the same side of the transversal and between the parallel lines are congruent.
Step-by-step explanation:
The consecutive interior angles theorem states that when two parallel lines, p and q, are cut by a transversal, t, the angles on the same side of the transversal and between the parallel lines are congruent.
In the given scenario, angles 1 and 2 are on the same side of the transversal and between the parallel lines, so according to the consecutive interior angles theorem, angles 1 and 2 must be congruent. Similarly, angles 2 and 3 are also on the same side of the transversal and between the parallel lines, so angles 2 and 3 must also be congruent.
Therefore, the correct relationship between angles 1, 2, and 3 is that angles 1 and 2 are congruent, and angles 2 and 3 are congruent. Option 2 is the correct answer.