Quadrilaterals

Dr. Beth McCulloch Vinson

Athens State University

PT3 Grant Funding, Summer 2000

“Quad” means four. Why would all of these shapes be called “quadrilaterals”?

Each shape has four sides.

square

parallelogram

rhombus

rectangle

Quadrilaterals

trapezoid

In this slide show you will learn that we identify

quadrilaterals by:

and the length of their sides.

their angles

Square• A square has four sides that are each the

same length. • It also has four right angles (perfect

corners). 1

2 3

4

Rhombus• A rhombus has four sides that are each the

same length. • But it has two acute and two obtuse angles.

acute

acuteobtuse

obtuse

Square and Rhombus

• A square and a rhombus both have four sides that are the same length. So, how are they different?

Square and Rhombus• A rhombus can be thought of as a slanted

square.• If we push on the left-hand side of this

square, it might end up looking like…

a rhombus.

The only difference between a square and a rhombus is

their angles.

Trapezoid• A trapezoid has four sides. • Two sides are parallel. • The opposing two sides are not parallel.

Those are parallel.

Those are not parallel.

Rectangle•A rectangle has four sides – two long sides and two short sides.

•Two sides are parallel.

•The opposing two sides are also parallel.

•It also has four right angles.

Parallelogram•A parallelogram has four sides – two long sides and two short sides.

•Two sides are parallel.

•The opposing two sides are also parallel.

•But, it has two acute and two obtuse angles.

Rectangle and Parallelogram

• A parallelogram can be thought of as a slanted rectangle.

• If we push on the left-hand side of this rectangle, it might end up looking like…

a parallelogram.

The only difference between a rectangle and a parallelogram

is their angles.

Use the following table to make comparisons using the

quadrilaterals.

For example, what do a square and a rectangle have in common?

QuadrilateralsSHAPE SIDES ANGLES PARALLEL

LINES

Square 4 same length

4 right angles 2 sets

Rhombus 4 same length

2 acute2 obtuse

2 sets

Trapezoid different lengths

different angles

1 set

Rectangle 2 long, 2 short

4 right angles 2 sets

Parallelogram 2 long, 2 short

2 acute 2 obtuse

2 sets

The End A Project Developed for

Preparing Tomorrow’s Teachers to Use Technology (PT3)

By Dr. Beth McCulloch Vinson

Athens State University, School of Education

http://www.athens.edu/vinsobm