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## 7th grade (Eureka Math/EngageNY)

### Course: 7th grade (Eureka Math/EngageNY) > Unit 1

Lesson 4: Topic D: Ratios of scale drawings- Exploring scale copies
- Explore scale copies
- Corresponding points and sides of scaled shapes
- Corresponding sides and points
- Identifying scale copies
- Identify scale copies
- Identifying scale factors
- Identify scale factor in scale drawings
- Identifying values in scale copies
- Scale drawing: centimeters to kilometers
- Making a scale drawing
- Construct scale drawings
- Interpreting a scale drawing
- Solving a scale drawing word problem
- Scale drawing word problems

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# Corresponding points and sides of scaled shapes

CCSS.Math:

Sal identifies corresponding sides and corresponding points in scale copies of figures.

## Want to join the conversation?

- what is in a line?(4 votes)
- hey hey hey hey hey hey(1 vote)

- Can someone run me through the pythagorean theorem and how we use it in these diagrams? I did the practice just fine without it.(4 votes)
- The Pythagorean Theorem is the equation a^2 + b^2 = c^2. With a right triangle, you look for the hypotenuse, which is the side that does not make up the right angle. You look for the measures of the sides that make up the right angle and put them in the a^2 + b^2. Continue solving until the solution is found.(6 votes)

- when it is a scaled copy does this mean that it will always be smaller than the original?(2 votes)
- A scaled copy of a shape is when the proportions of a shape stay the same, only the size changes. For example, lets say you have a square with 4 units for each side. A scaled copy of that square could be each side being 8 units or all side being 2 units. As long as the numbers stay proportional. Also, our 4 units per side square has an area of 16 units squared, and it's scaled copies have an area of 4 units squared (for the square to units per side), and 64 units squared (for the square with 8 units per side). See? All the numbers are proportional! Even 3D shapes can have scaled copies with proportional surface area and volume. Hope this helps!(1 vote)

- Its a dibolekol(2 votes)
- a line is straight(2 votes)
- but what if it isn't.. 🌈(1 vote)

- so we can do it JK or KJ side cuz i just did that(1 vote)
- Yep you can, I WOULD recommend up to down or left to right or KJ because yanno, JK LOL.

Sorry for late.(3 votes)

- does Sal make all the videos on Khan academy?(2 votes)
- No though he does make a lot of the, math ones if not all of them.(1 vote)

- TOES? do yo like(2 votes)
- what is in line(1 vote)
- The answer is JK(1 vote)

## Video transcript

- [Instructor] We are told figure two is a scaled copy of figure one. So this is figure two here. This is figure one. Looks like figure two not
only has it been scaled down, it's a smaller version, but it also looks like it
has been rotated 180 degrees or you can say it's been
flipped upside down. We're asked to identify
the side in figure two that corresponds to side EA in figure one. So this is EA in figure one. Pause this video and
see if you can identify the side of figure two that corresponds to side EA in figure one. Alright, now let's work
through this together. Some of you might immediately intuit or be able to spot which
side corresponds to EA but I'll do it slightly more
methodically in this video just so that we can see maybe all of the corresponding sides and points. So one way to think about it is well, it looks like the
longest side in figure one is side BC. So this is the longest side in figure one and then the longest
side in figure two is HL so it looks like BC corresponds to HL and then touching on that longest side, that longest side has two right angles. It forms two right angles
with the sides next to it. So you have these two right
angles right over here and then of those two right angles, you have the shorter side
connected to the longest side and so that is BA over here and so that would correspond
to LK right over here. That is the shorter side
connected to the long side that forms a right angle and then if we just keep
following that side of the shape, we then go to side AE which
would correspond now to and this is answering
our question to side KJ. So the side in figure two
that corresponds to EA in figure one, that is going to be KJ or we could say side JK and if someone wanted to say what points correspond to which point, well, you can see that
BA corresponds to LK and BC corresponds to LH so we would know for example that this point B right over here, point B would correspond to point L
in figure two right over here and we could use a similar
logic for the other points. So we've answered the
questions, the question, but the real thing is to see well, which sides or points have similar features on a relative basis? So I said what is the longest side? What is the longest side? Where do we see right angles? And sometimes your brain
might just immediately be able to spot out the shape. If you were to rotate this
one all the way around, it would jump out at
you a little bit faster that JK and AE are corresponding sides.