Step-by-step explanation:
You want a proof that angle 6 is congruent to angle 3.
Statement . . . . Reason
1. a║b, p║q . . . . given
2. The enclosed area is a parallelogram . . . . definition of a parallelogram
3. ∠6 ≅ ∠3 . . . . opposite angles of a parallelogram are congruent
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Additional comment
You may be expected to use the angle relations around parallel lines:
2. ∠6≅∠8 . . . . alternate interior angles are congruent
3. ∠8≅∠3 . . . . corresponding angles are congruent
4. ∠6≅∠3 . . . . transitive property of congruence