Main content

## Basic geometry and measurement

### Unit 14: Lesson 1

Transformations intro# Dilations intro

CCSS.Math:

An introduction to dilation which is a non-rigid transformation (distance between points is not preserved).

## Video transcript

- [Instructor] In previous
videos, we started talking about the idea of transformations. In particular, we talked
about rigid transformations. So for example, you can shift something. This would be a translation. So the thing that I'm moving
around is a translation of our original triangle. You could have a rotation. So that thing that I
translated, I am now rotating it as you see right over there. And you can also have a reflection. The tool that I'm using doesn't
make reflection too easy. But that's essentially
flipping it over a line. But what we're going to
talk about in this video is a non-rigid transformation. And what makes something
a rigid transformation is that lengths between
points are reserved. But in a non-rigid transformation, those lengths do not need to be preserved. So for example, this rotated
and translated triangle that I'm moving around right
here, in fact I'm continuing to translate it as I talk. I can dilate it. And one way to think about
dilation is that we're just scaling it down or scaling it up. So for example, here,
I am scaling it down. That is a dilation. Or I can scale it up. This is also a dilation or even going off of the graph paper. So the whole point
here's just to appreciate that we don't just have
the rigid transformations, we can have other types
of transformations, and a dilation is one
of them in your toolkit that you will often see,
especially when you get introduced to the idea of transformation.