6th Grade Math Textbook, Fundamentals

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BC

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BC|| AD

BA|| CD

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EF|| HG

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Quadrilaterals

Objective To identify the properties of quadrilaterals and the relationships among

different types of quadrilaterals• To apply the properties of quadrilaterals in finding missing

side and angle measures

Cindy and Rod are playing a Guess the Shape game
with quadrilaterals. Cindy constructed the figure
shown at the right. What types of quadrilaterals are
shown in Cindy’s figure? Which of the quadrilaterals
shown in the figure is neithera parallelogram nor
a trapezoid?

To answer the question, you need to explore
the different types of quadrilaterals and
their properties.

Quadrilaterals can be classified by the special

properties of their sides or angles.

A is a quadrilateral with two

pairs of parallel sides. Opposite sides and

opposite angles are congruent.

A is a parallelogram with four

right angles.

A is a parallelogram with four

congruent sides.

A is a parallelogram with four right

angles and four congruent sides.

A is a quadrilateral with exactly

one pair of parallel sides.

A is a quadrilateral with two pairs

of adjacent sides that are congruent.

The measures of its angles are each less

than 180.

So Cindy’s construction includes three trapezoids

and three parallelograms. The parallelograms include

a square and another rectangle that is not a square.

Since figure JBLKhas no parallel sides, it is neither

a parallelogram nor a trapezoid.

kite

trapezoid

square

rhombus

rectangle

parallelogram

 &KDSWHU

9-11

A

BC D

H

I

J

KL M

GF

E

Remember:Quadrilaterals are polygons

with four sides and four angles.