In quadrilateral abdc, ab ∥ cd. which additional piece of information is needed to determine that abdc is a parallelogram? ab ≅ cd ac ≅ bd ab ⊥ bd cd ⊥ bd

The answer is B AC ≅ BD Since you already know that ab ll cd, all you need to know is that ac is bd

B. AC ≅ BD

Step-by-step explanation:

Since the definition of a parallelogram literally says that it's a quadrilateral with 2 parallel sides, we have AB || CD so the 2 other sides (AC and BD) need to be either similar or parallel (either works, due to that if they're similar we can prove that since AB || CD that they're parallel).