Final answer:
The Converse of the Consecutive Interior Angles Theorem justifies that line ℓ is parallel to line m.
Step-by-step explanation:
The postulate or theorem that justifies the fact that ℓ || m given m∠6 + m∠7 = 180 is the Converse of the Consecutive Interior Angles Theorem (option d).
- According to the Converse of the Consecutive Interior Angles Theorem, if two lines are cut by a transversal and the consecutive interior angles are supplementary (add up to 180 degrees), then the lines are parallel. In this case, angles 6 and 7 are consecutive interior angles and their sum is 180 degrees, which means that the lines ℓ and m are parallel.