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WARM UPName 5 properties of parallelograms.
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92 Conditions for Parallelograms
We have learned the properties of a parallelogram. Now we will be given the properties of a quadrilateral
and will have to tell if the quadrilateral is a parallelogram.
To do this, we willuse the definition of a parallelogram
or the following conditions.
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Theorem 95
If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a parallelogram.
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Theorem 96
If one pair of opposite sides of a quadrilateral are both congruent and parallel, then the quadrilateral is a parallelogram.
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Theorem 97
If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram.
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Theorem 98
If both pairs of opposite angles of a quadrilateral are congruent, then the quadrilateral is a parallelogram.
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Determine if the quadrilateral must be a parallelogram. Justify your answer.
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Show that JKLM is a parallelogram for a = 3 and b = 9.
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You have learned several ways to determine whether a quadrilateral is a parallelogram. You can use the given information about a figure to
decide which condition is best to apply.
To show that a quadrilateral is a parallelogram, you only have to show that it satisfies one of these sets of conditions.
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HW # 104
p. 45758 # 1 14, 18 21
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