Answer:
AB is ║ to CD( property of parallelogram)
∠ABD is congruent to ∠CDB( Angles opposite of equal sides are congruent)
BD=BD( Reflexive property),
Step-by-step explanation:
Given: ABCD is a parallelogram with diagonal line segment BD.
Proof: In ΔABD and ΔCBD,we have:
AB is parallel to CD( Property of paralleogram),
∠ABD is congruent to ∠CDB( Angles opposite of equal sides are congruent)
BD=BD( Reflexive property),
Therefore, ΔABD≅ ΔCBD,