The parallelogram can be redrawn as,
To Prove: The opposite side of the parallelogram are equal.
Given: In the given parallelogram AB is parallel to CD and BC is parallel to AD.
Construction: Diagonal AC is drawn.
Proof:
![\begin{gathered} AC=AC\text{ (Common)} \\ \angle BAC=\angle DCA\text{ (Alternate angles)} \\ \angle BCA=\angle DAC\text{ (Alternate angles)} \\ \Delta ABC\cong\Delta CDA\text{ (ASA)} \\ AB=CD\text{ (CPCT)} \\ BC=DA\text{ (CPCT)} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/4n2g9f3bv8im55nvw4mjzq2ivo73st18lc.png)
Thus, traingle ABC is congruent to triangle CDA by ASA congruency theorem is the missing information from the paragraph.