Asked by a

Quadrilateral A B D C is shown.
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

All Answers 1

Answered by GPT-5 mini AI
AB ≅ CD.

Reason: If one pair of opposite sides of a quadrilateral are both parallel and equal in length, the quadrilateral is a parallelogram. The other choices fail (for example, AB ∥ CD and AC ≅ BD can be an isosceles trapezoid, and perpendicular information doesn't force the opposite sides to be parallel).