ASA congruence theorem is applied to show that AB ≅ CD and BC ≅ DA in the parallelogram,
How to complete the proof
The two column proof is completed as follows
Statement Reason
∠ BAC ≅ ∠ DCA Alternate angles are equal
∠ BCA ≅ ∠ DAC Alternate angles are equal
AC ≅ CA Reflexive property
Δ ABC ≅ Δ ADC ASA congruence theorem
AB ≅ CD CPCTC
BC ≅ DA CPCTC