Dilations

Dilations

Please read through each slide carefully. After this lesson, you will know all about dilations!

Dilation means that the size of the figure will change. The figure will get LARGER or SMALLER. Dilations produce SIMILAR FIGURES - meaning same shape but different size.

How will the figure change?

• It can stretch or get larger.

• It can shrink or get smaller.

Enlarging/Stretching

An Figure:

• If you have a scale factor greater than 1, the figure will get bigger.

• For example, if the scale factor is 2, the figure will double in size.

Shrinking a Figure:

• If you have a scale factor that is less than 1, the image will get smaller.

• For example, if the scale factor is 1/2 or 0.5, the image will be half the size of the pre-image.

How does it change?

MULTIPLY the coordinates by the Scale Factor.

Scale Factor of 1

• This means the figure stays the same size.

• This is uncommon as the figure does not change from pre-image to image.

Example of a Scale Factor greater than 1

• The figure has stretched or been enlarged.

• The pre-image is the purple triangle and the image is the green triangle.

So what is the Scale Factor?

Let's look at one of the points.

Point C (2, 1)

Point C' (4, 2)

How did the points increase?

Answer: Each coordinate was multiplied by 2. Therefore the scale factor is 2!

Example of a Scale Factor is less than 1

• The figure has shrunk.

• The pre-image is the purple triangle and the image is the blue triangle.

What is the Scale Factor?

Let's look at one of the points - pick any point.

Point A (2, 6)

Point A' (1, 3)

How did the coordinates change?

The numbers got smaller. Each number was divided by 2. This means that the scale factor is 1/2.

Now complete your classwork assignment on Dilations.

Quizizz Code: 35188754

Use your FIRST & LAST Name

This will be a classwork grade and you can complete the assignment more than once.