Final answer:
The fact that angles 6 and 7 are supplementary suggests they may be consecutive interior angles on parallel lines, proven using the Consecutive Interior Angles Theorem.
Step-by-step explanation:
If angles 6 and 7 are supplementary, it means that their measures add up to 180 degrees. This situation often arises in the case of parallel lines cut by a transversal. According to the Consecutive Interior Angles Theorem, if a transversal intersects two parallel lines, then each pair of consecutive interior angles is supplementary. If angle 6 and angle 7 are consecutive interior angles, the fact that they are supplementary would allow us to use this theorem to prove that lines j and k are parallel (j∥k).