Answer :
The Solution:
Required:
To prove that opposite sides are congruent in a parallelogram.
Step 1:
Draw a parallelogram.
Step 2:
[tex]DB\cong DB\text{ \lparen Reason: Reflexive property\rparen}[/tex]Step 3:
[tex]AB\parallel CD\text{ and BC }\parallel AD\text{ \lparen Reason: Definition of a parallelogram\rparen}[/tex]Step 4:
[tex]\angle1\cong\angle4\text{ and }\angle2\cong\angle3\text{ \lparen Reason: Alternative angles are equal.\rparen}[/tex]Step 5:
[tex]\angle ABD\cong\angle CDB\text{ \lparen Reason: Angle-Side-Angle \lparen ASA\rparen Theorem\rparen}[/tex]Step 6:
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