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

Writing equations to represent geometric problems | Grade 8 (TX TEKS) | Khan Academy


less than 1m read
·Nov 10, 2024

We're told the perimeter of the rectangle shown is 17x units. The area of the rectangle is 15x square units. Write an equation that represents the perimeter, and also write an equation that represents the area.

So pause this video and see if you can write those two equations.

All right, now let's do this together. So let's tackle this first one. Write an equation that represents the perimeter. The perimeter is going to be the length of all of the sides. So you have this side right over here which is 4x + 2, and then you're going to add this side over here, which is 2 and a half, plus this side over here which is going to be 4x + 2 again. So, plus 4x + 2, plus this side which is going to be 2 and A2 plus 2 and a half. Well, that's going to be equal to the perimeter, which they told us is 17x units. So that is going to be equal to 17x.

And we're done! That's all they wanted; they just want us to write an equation that represents the perimeter. We don't have to solve it.

So now let's do the same thing for the area. The area of a rectangle is going to be our base times our height, or our height times our base. So we could say it's 2 and A2 * (4x + 2). Then, that's going to be our area, which they say is 15x² units. So that's equal to 15x. We could have also written it the other way; we could have said that the area, which is 15x, is equal to 2 and A2, the height, times (4x + 2).

So, a lot of different ways to approach it, but in both cases, we are now done.

More Articles

View All
Electromagnetic waves | Physics | Khan Academy
What’s common between a Wi-Fi router, our bodies, and an incandescent bulb? We all give out electromagnetic waves. But why do we do that? And why are they all so different? How do we use some of them for wireless communications? Let’s answer all of them. …
Continuity-Sikhism connections to Hinduism and Islam | 1450 - Present | World History | Khan Academy
In previous videos, we’ve gone into reasonable depth on the narrative of how the Sikh religion was started initially by Guru Nanak, and then it has developed under the next gurus all the way until the tenth Guru and finally as it was compiled in the Guru …
Citizenship in early America, 1840s-1870s | Citizenship | High school civics | Khan Academy
In the last video, we discussed who did and did not have citizenship and voting rights from 1789 to the 1830s. To summarize, citizenship was reserved for white men, women, and children. By the 1830s, the right to vote extended to all white men, regardless…
The truly irregular verbs | The parts of speech | Grammar | Khan Academy
Hello Garans, welcome to the last and strangest part of the irregular verb: the truly irregular. Yes, friends, here I have compiled all the weirdest, all the wooliest, all the eeriest and spookiest forms of verbs that don’t otherwise fall into other categ…
Human Cow BREAST MILK??? -- Mind Blow #18
A vending machine toy capsule wall and Charlie Sheen mask. Vsauce, Kevin here. This is Mind Blow. You know Mario Kart’s Rainbow Road? Well, here’s the rainbow walkway. It’s a 52 metre panorama located on the roof of a building in Denmark, and visitors ca…
How NASA Reinvented The Wheel
This metal is about as close to magic as it is possible to find in nature. I just don’t get it. It can adjust its arrangement of atoms to return to some predefined shape, but it also converts between mechanical and thermal energy. And it can stretch up to…