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8.2 & 8.3 - Properties of Parallelograms. Parallelogram:. Quadrilateral with both pairs of opposite sides parallel. Theorem: If a quadrilateral is a parallelogram, then both pairs of ___________ sides are ______________. opposite. congruent. Theorem:
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Parallelogram: Quadrilateral with both pairs of opposite sides parallel
Theorem: If a quadrilateral is a parallelogram, then both pairs of ___________ sides are ______________. opposite congruent
Theorem: If a quadrilateral is a parallelogram, then both pairs of ___________ angles are _____________. congruent opposite
Theorem: If a quadrilateral is a parallelogram, then both pairs of ___________ angles are _____________. consecutive supplementary A B mA + mB = 180° mA + mD = 180° mB + mC = 180° C D mC + mD = 180°
Theorem: If a quadrilateral is a parallelogram, then both diagonals _______________ each other. bisect
1. Find the value of each variable in the parallelogram. 8 11
1. Find the value of each variable in the parallelogram. a – 3 = 14 a = 17 b + 2 = 7 b = 5
1. Find the value of each variable in the parallelogram. g + 7 = 15 g = 8 h – 8 = 12 h = 20
1. Find the value of each variable in the parallelogram. 3x + 6 = 12 3x = 6 x = 2 2y + 9 = 27 2y = 18 y = 9
2. Find mB and mC. 119° 61°
3. Find mJ and mK. 102° 78°
4. Find the value of each variable in the parallelogram. x + 2 3x = 6 x = 2 3x 6 x + 2 = y – 1 y – 1 2 + 2 = y – 1 4 = y – 1 5 = y
4. Find the value of each variable in the parallelogram. 9b – 2 = 106 9b = 108 b = 12° 7a – 3 + 106 = 180 7a + 103 = 180 7a = 77 a = 11°
4. Find the value of each variable in the parallelogram. 5q + 4 = 49 5q = 45 q = 9 2p = 124 p = 62°
16 HI = _________ Opposite sides
8 GH = _________ Diagonals bisect each other
10 KH = _________ Opposite sides
16 HJ = _________ 8 Diagonals bisect each other
28° KIH = _________ Alternate interior angles
180 – 84 = 96° JIH = _________ Consecutive angles are supplementary
84° KJI = _________ Opposite angles are
96 – 28 = 68° HKI = _________ 96° Opposite angles are
congruent parallelogram
congruent parallelogram
supplementary parallelogram
bisect parallelogram
congruent parallel parallelogram
What theorem can you use to show the quadrilateral is a parallelogram? one pair of opposite sides are congruent and parallel
What theorem can you use to show the quadrilateral is a parallelogram? the diagonals bisect each other
What theorem can you use to show the quadrilateral is a parallelogram? both pairs of opposite sides are congruent
What theorem can you use to show the quadrilateral is a parallelogram? both pairs of opposite angles are congruent
Is the quadrilateral a parallelogram? Explain. No, Both pairs of opposite sides are not parallel
Is the quadrilateral a parallelogram? Explain. Yes, Both pairs of opposite sides are congruent
Is the quadrilateral a parallelogram? Explain. No, Not a quadrilateral!
Is the quadrilateral a parallelogram? Explain. No, Opposite sides are not congruent
What additional information is needed in order to prove that quadrilateral ABCD is a parallelogram?
What additional information is needed in order to prove that quadrilateral ABCD is a parallelogram?
What additional information is needed in order to prove that quadrilateral ABCD is a parallelogram?
What additional information is needed in order to prove that quadrilateral ABCD is a parallelogram? mCDA + mDAB = 180° mCDA + mDCB = 180°
What additional information is needed in order to prove that quadrilateral ABCD is a parallelogram? DCB DAB CDA CBA
HW Problem 8.2 #34 Ans: –2x + 37 = x – 5 M 4y + 5 N x = 14 –2x + 37 x – 5 4y + 5 = y + 14 y = 3 Q y+ 14 P P = 17 + 17 + 9 + 9 = 52u