- ASAS
- BSSS
- CASA
- DAAS
Step-by-Step Solution
AB = CD (given), ∠ABD = ∠CDB (alternate angles, AB ∥ DC) and BD is common. The angle lies between AB and BD (and between CD and DB), so SAS. It follows that AD = CB, so ABCD is a parallelogram.
Answer: A) SAS