yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Identifying scale factors


2m read
·Nov 11, 2024

So right over here, figure B is a scaled copy of figure A. What we want to do is figure out what is the scale factor to go from figure A to figure B. Pause the video and see if you can figure that out.

Well, all we have to do is look at corresponding sides and think about how much they have been scaled by. So, for example, this side right over here would correspond to this side right over here on figure B. Over here, it had length two, and over here, it has length one, two, three, four, five, six. So, it looks like that side has been scaled up by a factor of three.

If figure B truly is a scaled copy, then every side should be scaled up by a factor of three. We could verify that; we don't have to do it with every side. We're being told that these are scaled copies, but we can see that this is the case. For example, this side right over here corresponds to this base right over here. This has length three.

So, if we're scaling up by a factor of three, we should multiply that by three, and this should be of length nine. Let's see if that's the case: one, two, three, four, five, six, seven, eight, and nine. You can see we can feel pretty good that figure B is a scaled copy of figure A, and that scaling factor is three.

Let’s do another example. Here we are told Ismail made a scaled copy of the following quadrilateral. He used a scale factor less than one. All right, and then they say, what could be the length of the side that corresponds to AD?

So, AD is right over here. AD has length 16 units in our original quadrilateral. What could be the length of the side that corresponds with AD on the scaled copy of the quadrilateral? Since it's a scale factor less than one, we're going to get something that is less than 16 for that side. The rest of it will all be scaled by the same factors.

So, the resulting quadrilateral might look something like this; this is just my hand-drawn version. The key realization is if our scale factor is less than 1, this thing right over here is going to be less than 16 units.

So, let's look at the choices, and it says choose three answers. Pause the video. Which of these would match if we're scaling by a factor of less than one? Well, we just have to see which of these are less than 16 units. This is less than 16; this is less than 16; this is less than 16. Those are the only three that are less than 16.

32 units would be a scale factor of 2. 64 units would be a scale factor of 4, clearly a scale factor that is not less than 1.

More Articles

View All
15 Ways To DECLUTTER Your Life
When you were little, remember when your mum used to tell you to tidy your room? Yes, we’re going to remind you of that good advice your mom gave you, but we’re going to take it quite a bit further too. Hey, Aluxers! Watch this video right until the end,…
We made a Video Game (FISH GAME) - Smarter Every Day 291
Hey, it’s me, Destin. Welcome back to Smarter Every Day. We made a video game. I was supposed to make a video here about, like, “Hey, this is the game, and you can buy it, and you can play it, and it’s awesome.” That was the original idea for this. But th…
Inside The Most Powerful Startup Community In The World
In 2005, four people came together to make something new. They thought if we bring together smart technologists and give them a little bit of money and a really good community, it would give founders a huge advantage. Out of that first Y Combinator batch …
Sergey Brin | All-In Summit 2024
They wondered if there was a better way to find information on the web. On September 15th, 1997, they registered Google as a website. One of the greatest entrepreneurs of our times, someone who really wanted to think outside the box, if that sounds like i…
Khan Academy Ed Talks with Ted Coe, PhD - Tuesday, March 15
Hello and welcome to Ed Talks with Khan Academy. I’m Kristen Decervo, the Chief Learning Officer at Khan Academy, and today I am looking forward to talking to Dr. Ted Co., who is with NWEA, one of our key partners. Here he is the Director of Content Advoc…
The Fall of Empires | World History | Khan Academy
Steve: “What are we doing here? Hey, sell, we’re going to look at this question of why do Empires fall. For those of you who don’t know, Steve Shrer, he is a world history fellow here at Khan Academy, and also a former world history teacher. So, what we …