Properties of Dilations, Day 2

How do you describe the properties of dilations?

Dilations change the size of figures, but not their orientation or shape.

What is the same for the dilated figure and its image?

What is different?

The shapes are the same; the orientation is the same; the sizes are different.

The scale factor is always new over original, or image over pre-image.

You are given a graph of a dilation and asked to identify its scale factor and

whether it is an enlargement or a reduction. What do you look for?

Look for the prime marks to indicate the image; if the image is larger than the

original, it is an enlargement and the scale factor will be greater than one. Find the

ratio of the new side lengths to the original to find the scale factor.

Explain how you can find the center of dilation of a triangle and

its dilation.

Locate the corresponding vertices of the triangles and draw lines

connecting each pair. The lines will intersect at the center of dilation.

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