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What do you think?. Theorem 8.7: If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram. Theorem 8.8: If both pairs of opposite angles of a quadrilateral are congruent, then the quadrilateral is a parallelogram.
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Theorem 8.7: If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram.
Theorem 8.8: If both pairs of opposite angles of a quadrilateral are congruent, then the quadrilateral is a parallelogram.
Theorem 8.9: If one pair of opposite sides of a quadrilateral are congruent and parallel, then the quadrilateral is a parallelogram.
Theorem 8.10: If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a parallelogram.
Explain how you know that quadrilateral QRST is a parallelogram.
Which theorem can be used to show that the quadrilateral is a parallelogram?
Summary Ways to prove a quadrilateral is a parallelogram. • Show both pairs of opposite sides are parallel. • Show both pairs of opposite sides are congruent. • Show both pairs of opposite angles are congruent. • Show one pair of opposite sides are both parallel and congruent. • Show that diagonals bisect each other.