6.4 Special Parallelograms
Brett SolbergAHS ‘11-’12
Warm-up

1) Solve for x, y, and z.

2) Solve for x and y
What HW questions do you want to review?
Today’s Agenda
Quiz
 Special Parallelograms

◦ Rhombus
◦ Rectangle
1/10 6.5
 1/12 Review/Test

Quiz
You can use your notes.
 Read the directions carefully.
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Rhombus
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A Rhombus is a parallelogram with
congruent side lengths.
Theorem 6.9

Each diagonal of a rhombus bisects 2
angles.
Example 1
Theorem 6.10
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The diagonals of a rhombus are
perpendicular.
Example 2
Geogebra

Visualizing the theorems
Converses
6.9 – If a parallelogram is a rhombus, then
each diagonal bisects 2 angles.
 6.12 – If a diagonal in a parallelogram
bisects 2 angles, then the parallelogram is
a rhombus.
 6.10 – If a parallelogram is a rhombus,
then the diagonals are perpendicular.
 6.13 – If the diagonals of a parallelogram
are perpendicular, then the parallelogram
is a rhombus.
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Rectangle

A parallelogram with 4 right angles.
Rectangle

6.11 If a parallelogram is a rectangle ,then
the diagonals are congruent
◦ DF = GE

6.14 If the diagonals of a parallelogram are
congruent, then the parallelogram is a
rectangle.
Example 3
FD = 2x + 4
 GE = 6x - 5
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Homework

6.4 Worksheet and pg 332 # 1-20 even