Informal Geometry 8.2 Parallelograms
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Informal Informal Geometry Geometry 8.2 8.2 Parallelograms Parallelograms
description
Informal Geometry 8.2 Parallelograms. -A parallelogram is a quadrilateral with both pairs of opposite sides parallel. -The symbol PQRS is read “parallelogram PQRS.”. If a quadrilateral is a parallelogram, then its opposite angles are congruent. Theorem 8.2. Q. R. P. S. - PowerPoint PPT Presentation
Transcript of Informal Geometry 8.2 Parallelograms
InformalInformalGeometryGeometry
8.2 8.2 ParallelogramsParallelograms
-A parallelogram is a quadrilateral with both pairs of opposite sides parallel.
-The symbol PQRS is read “parallelogram PQRS.”
Theorem 8.2Theorem 8.2
• If a quadrilateral is a parallelogram, then its opposite angles are congruent.
P
Q R
S
Theorem 8.3Theorem 8.3
• If a quadrilateral is a parallelogram, then its opposite sides are congruent.
P
Q R
S
Theorem 8.4Theorem 8.4
• If a quadrilateral is a parallelogram, then its consecutive angles are supplementary (add up to 180°).
mP +mQ = 180°,
mQ +mR = 180°P
Q R
S
Theorem 8.5Theorem 8.5
• If a quadrilateral is a parallelogram, then its diagonals bisect each other.
P
Q R
S
Ex. 1Ex. 1
• FGHJ is a parallelogram. Find the unknown length. Explain your reasoning.
a. JH
b. JK
F G
J H
K
5
3
b.
Ex. 2Ex. 2
PQRS is a parallelogram.
Find the angle measure.
a. mR
b. mQ P
RQ
70°
S
Ex. 3: Using Algebra with ParallelogramsEx. 3: Using Algebra with Parallelograms
PQRS is a parallelogram. Find the value of x.
S
QP
R(3x+30)° 120°
HomeworkHomework
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