If both pairs of opposite sides are parallel, then the quadrilateral is a parallelogram. Condition #3: If both pairs of opposite angles are congruent, then the quadrilateral is a parallelogram. Condition #4: If an angle is supplementary to both consecutive angles, then the quadrilateral is a parallelogram.
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sakurachan13
Well, we must show one of the six basic properties of parallelograms to be true! Both pairs of opposite sides are parallel. Both pairs of opposite sides are congruent. Both pairs of opposite angles are congruent. Diagonals bisect each other. One angle is supplementary to both consecutive angles (same-side interior)
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Answer:
If both pairs of opposite sides are parallel, then the quadrilateral is a parallelogram. Condition #3: If both pairs of opposite angles are congruent, then the quadrilateral is a parallelogram. Condition #4: If an angle is supplementary to both consecutive angles, then the quadrilateral is a parallelogram.
Both pairs of opposite sides are parallel.
Both pairs of opposite sides are congruent.
Both pairs of opposite angles are congruent.
Diagonals bisect each other.
One angle is supplementary to both consecutive angles (same-side interior)