Question

The following is an incomplete paragraph proving that the opposite sides of parallelogram ABCD are congruent:

Answer 1

Answer:  Triangles BCA and DAC are congruent according to the Angle-Side-Angle (ASA) Theorem.

Step-by-step explanation:

Given : ABCD is a parallelogram.

That is, AB ║ CD and AD ║BC

We have to prove that: AB≅CD and AD≅BC

Proof:

Construct diagonal AC in the parallelogram ABCD.

Since, AC ≅ AC ( reflexive)

∠ BAC ≅ ∠ DCA  ( By the alternative interior angle theorem)

∠ BCA ≅ ∠ DAC   ( By the alternative interior angle theorem)

⇒ Δ BCA ≅ Δ DAC ( By ASA congruence postulate )

⇒ AB≅CD as well as AD≅BC ( BY CPCTC )

Thus, the opposite side of the parallelogram are congruent.