3. Tests for Parallelograms
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What conditions must a quadrilateral satisfy to be a parallelogram?
Yes; each pair of opposite angles are congruent.
To prove that a quadrilateral is a parallelogram, it is enough to show that one of the following conditions is satisfied.
Let's analyze the given quadrilateral.
Looking at the angle markings, we can see that both pairs of opposite angles are congruent. Therefore, it is a parallelogram.