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Geometry Notes
Section 6.2 Parallelograms
Quadrilateral: a polygon with _____ sides
Parallelogram: a quadrilateral with both pairs of opposite sides parallel
To name a parallelogram, we use the symbol
Properties of Parallelograms
Thm: Opposite sides of a parallelogram are congruent.
Thm: Opposite angles of a parallelogram are congruent.
Thm: Consecutive angles of a parallelogram are supplementary.
𝑥° + 𝑦° = 180°
Thm: If a parallelogram has 1 right angle, then it has 4 right angles.
B
C
Thm: The diagonals of a parallelogram bisect each other.
30
E
A
D
A
1
D
4
Examples:
2
C
2𝑥 − 4
F
1. Find the value of x and y in parallelogram EFGH.
B
3
Thm: A diagonal of a parallelogram divides the parallelogram
into two congruent triangles.
G
4𝑥
𝑥 − 15
E
3𝑦
A
2. Given parallelogram ABCD, find the measure of each angle.
H
B
(3x +25 )
D
(5x-5)
C
Ex: WXYZ is a parallelogram.
a. Find YZ.
b. Find mZ.
Ex: If WXYZ is a parallelogram, find:
a. Find r
𝑉
b. Find s
c. Find XZ
d. Find t
e. Find mWZY
Ex: In
CDEF, DE = 74 mm, DG = 31 mm, and mFCD = 42°.
a. Find CF.
b. Find mEFC.
c. Find DF.
Assignment: Sec. 6.2 p.407 # 9 – 12, 15 – 20, 31 – 36
Show your work!
(16 probs)