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### Course: 7th grade (Illustrative Mathematics) > Unit 1

Lesson 1: Lesson 1: What are scaled copies?# Exploring scale copies

Sal uses virtual manipulatives to identify figures that scale proportionally.

## Want to join the conversation?

- i need help because this is very hard(22 votes)
- The scale copy increases from all sides but if it is not increasing from all sides that means it not a scales copy(13 votes)

- Did I just watch a Kahn video by myself NO(19 votes)
- Yes I believe so unless you are in class or someone is watching you!(10 votes)

- who needs reddit when you have the comment section of a khan academy video.(17 votes)
- what are scaled copies(7 votes)
- Scaled copies are a bigger version of a shape. I.E, if I have a polygon that has a perimeter of...10(length is 5 width is 2) and I want to scale it by 2, my new perimeter should be 40, because 5*2= 10 and 2*2= 4, 4*10= 40.(15 votes)

- i dont understand(9 votes)
- If someone could please provide me a real-life example of this that would be much appreciated!(4 votes)
- Pretend you are buying a decoration. You can choose to buy it 3 inches by 6 inches or pay $3 extra to buy it 4 inches by 8 inches.

The sizes would be a scale copy. The measurements are both multiplyed by 4/3 if you pay more money.

Here is a challenge.

1. If the cost was proportional with the size, what would the measurements be for one that cost $6 extra?

Answer: 5 inches by 10 inches(4 votes)

- i dont know what to ask(3 votes)
- Ask when they will install calculators...(6 votes)

- need help because it is hard(5 votes)
- Totally needed this. I Got 100% on the test and told the teacher I was done. She said, "You watched the video too?" I was like ummm no why. And said did I need to?(5 votes)
- For anybody that needs help it is which ever slider keeps it shape or "width".(2 votes)

## Video transcript

- [Instructor] We are
told, "Drag the sliders." And then they say, "Which
slider creates a scale "copy of the shape?" Or, "Which slider creates
scale copies of the shape?" So let's just see and
explore this a little bit. Okay, that's pretty neat,
these sliders seem to change the shape in some way,
and in different ways. So shape B right over
here, so it starts off, it looks like the width
is a little bit bigger than the height, I'm just
trying to eyeball it, we don't know the exact numbers. And so in order to create a scaled copy, you'd want to scale the
width, you'd want to scale this bottom side, and the top
side, and all of the sides. You'd want to scale by the same factor. But as we move this slider,
it seems like it's only scaling the width, it's
not scaling the height. So this slider, shape B right over here, the slider for shape B is not creating scale copies of itself, it's
only increasing the width, not the height. While shape A, it looks
like it is increasing both the width and the height, so that would be a scale copy. So for example, that looks
like a scale copy of this, which looks like a scale copy of this, which looks like a scale copy of that, which was our original shape. That is not a scaled copy of this. Let's do another example. So once again they say,
"Drag the sliders." And they say, "Which
slider creates a scale copy "of the shape?" All right, let's get shape A. So this does look like we're scaling down, but we're scaling both
the width and the height by the same factor, so this shape A slider does look like it's creating
scale copies of the shape. B right over here, well
now we're only scaling, it looks like we're
only scaling the height, but not the width, so this
is not creating scale copies of our original shape. It's elongating it, it's
increasing its height, but not the width.