geometric proofs?

http://prntscr.com/8r77ua

A student wrote the following sentences to prove that parallelogram ABCD has two pairs of opposite sides equal:

For triangles ABD and CDB, alternate interior angle ABD is congruent to angle CDB because AB and DC are parallel lines. Similarly, alternate interior angle ADB is equal to angle CBD because AD and BC are parallel lines. DB is equal to DB by reflexive property. Therefore, triangles ABD and CDB are congruent by _______________. Therefore, AB is congruent to DC and AD is congruent to BC by CPCTC.

Question

geometric proofs? 

http://prntscr.com/8r77ua

A student wrote the following sentences to prove that parallelogram ABCD has two pairs of opposite sides equal:

For triangles ABD and CDB, alternate interior angle ABD is congruent to angle CDB because AB and DC are parallel lines. Similarly, alternate interior angle ADB is equal to angle CBD because AD and BC are parallel lines. DB is equal to DB by reflexive property. Therefore, triangles ABD and CDB are congruent by _______________. Therefore, AB is congruent to DC and AD is congruent to BC by CPCTC.

leahhhmorgannn · Answer

Which phrase best completes the student's proof?

 ASA Postulate

 HL Postulate

 SAS Postulate

 SSS Postulate

leahhhmorgannn · Answer

I picked SSS, but got it wrong. Can someone help me understand this more so I'll know how to do it in the future?

leahhhmorgannn · Answer

@ganeshie8

ganeshie8 · Answer

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