geometry

What is Geometry?

By Alan Kagan

Lesson 1:

Area of squares and rectangles

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Exploration of Sides Sources

What is Geometry?

Menu

Use the menu to the left to navigate around this PowerPoint to the various sections.Key

Area Activity

Area of a RectangleAREA

Area of a SquareAREA

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What is Geometry?

Geometry is the study of 2-D and3-D shapes.

Traits such as angles and the number of sides (or surfaces) are

used to classify shapes.

Click on the shapes to Click on the shapes to

hear their names!hear their names!

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How many sides do I have?

Click on the image below and count the sides of the square.

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Count the sides…

Can you count the sides of the shapes?

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Count the sides…

Can you count the sides of the shapes?

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Area of a Square

How do we find area of a square?

To find the area (or the amount of space on the surface of the shape), we use the simple equation:

Length x Width = Area(squared in.,

squared ft. etc.)

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Area of a Square

Example:

Square not drawn to scale

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Area of a Square

Now it’s your turn! Find the area of the square below.

What is the area of this square?

Square not drawn to scale

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Area of a Square

Let’s try one more…Find the area of the square below.

What is the area of this square?

Square not drawn to scale

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Area of a Rectangle

How do we find area of a rectangle?

To find the area of a rectangle (or the amount of space on the surface of the shape), we use the same simple equation:

Length x Width = Area (squared in.,

squared ft. etc.)

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Area of a Rectangle

Example:

Square not drawn to scale

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Area of a Rectangle

Now it’s your turn! Find the area of the rectangle below.

What is the area of this rectangle?

Square not drawn to scale

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Area of a Rectangle

Let’s try one more…Find the area of the rectangle below.

What is the area of this rectangle?

Rectangle not drawn to scale

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How many squares can I fit?

Now that you are an expert on area of squares and rectangles, can you use that knowledge to

estimate how many small squares you can fit into a

larger square?

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How Many Squares Fit?

To start, it helps to look at the length and width of both squares.

Rectangle not drawn to scale

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How Many Squares Fit?

Now, how would you figure out how many red squares would

fit into the blue

square?

How many red squares do you think will

fit into the blue square?

How do you know

this?

Rectangle not drawn to scale

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How Many Squares Fit?

Let’s count the number of red squares that can fit into the blue square.

Rectangle not drawn to scale

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Why is it important to know area?

Gardening Construction Installing carpet, tiles Table Cloths/ Sheets

Can you think of any more reasons?

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In Class Activity

Now, look around the room for square or rectangular objects.

– Use a ruler to measure the objects and use a calculator for any big numbers.

– Make a chart and write down the name of the object, shape, length, width, equation and area of the object.

(REMEMBER TO USE LABLES.)

Object Shape Length Width Equation Area

Desk Rect. 18 in. 24 in. 18 in x 24 in.= 432 sq. in.

432 sq. in

Window

Square

10 in. 10 in. 10 in. x 10 in. = 100 sq. in.

100 sq in.

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Sources

http://en.wikipedia.org/wiki/Geometry http://www.nctm.org/standards/

focalpoints.aspx?id=326

“Mr. Smith’s Tiling Company” accompanying WebQuest made by Alan Kagan– http://zunal.com/webquest.php?

user=12191