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

Perimeter word problem (skating rink) | Math | 3rd grade | Khan Academy


2m read
·Nov 11, 2024

Gus plans to install a handrail around a skating rink. The rink forms a 40 meter by 20 meter rectangle. How many meters of handrail does Gus need?

So here's what we know about this skating rink: it's a 40 meter by 20 meter rectangle. So let's draw the skating rink; that might help us to visualize. We know that one side length is 40 meters, and another side length is 20 meters.

So Gus definitely needs to put some handrails 40 meters here and 20 meters here. But that is not enough. As somebody who doesn't know how to skate, I very much hope Gus puts handrail on this length and this length also. He needs to put the handrails all the way around the outside, or what we could call the perimeter of the shape. The entire distance around the outside.

Because this skating rink is a rectangle, we know that opposite sides are equal. So if this length is 40 meters up here, then this length down here must also be 40 meters. And we can do the same thing with 20. If we have 20 over here, then the length across must also be 20 meters.

So now we can figure out the entire amount of handrail Gus needs; the amount of meters he needs to buy to put around the skating rink. For this first side here, he needs 40 meters. Plus, to go down this side, he'll need another 20 meters of handrail. Going across the bottom of the rink, he'll need another 40 meters of handrail.

And then, going up the side, he'll need another 20 meters of handrail. So we can add these to find the total amount he needs.

40 plus 20 is 60. Then, 60 plus 40 plus 40 is 100, and 100 plus 20 more is 120 meters.

So, to go the entire distance around the outside of the skating rink, or the perimeter of the skating rink with handrail, Gus will need 120 meters of handrail.

More Articles

View All
These are the most INSANE mansions of Beverly Hills 90210
Let’s see if we can clear this without scraping. Make sure to smash that like button. If this video gets three thousand likes, then I’m not gonna scrape; otherwise, if it doesn’t get three thousand likes, I’m gonna scrape my bumper pretty bad here. Oh, w…
The Most Controversial Problem in Philosophy
Do not hit the like button! Or the dislike button, at least not yet. I want you to consider a problem that’s been one of the most controversial in math and philosophy over the past 20 years. There is no consensus answer. So I want you to listen to the pro…
The 5 BEST Credit Cards For Cash Back
What’s of you guys? It’s Graham here. So, after the recent popularity of the Apple credit card video, it came to my attention that a lot of people were focusing on the 2% cashback on the products purchased through Apple Pay and then also focusing on the …
15 Steps to Fix a Broke Mindset
It’s not the empty pocket holding you back. It’s not your lack of connections or being born with a silver spoon in your mouth. Unless you were born with a severe disability or a country ridden by war, you’ve got a real shot at building wealth. If you’re w…
What I Wish I Knew When I Was Younger
Welcome to beautiful Vancouver, British Columbia. This is actually where I grew up, just across that water. And I remember when I was a teenager here I wanted to be a film maker. And so what did I do? Well, I found a film director with a strange name who …
Seven Wonders of the New World | Cosmos: Possible Worlds
NEIL DEGRASSE TYSON: We all feel the weight of the shadows on our future. But in another time, every bit as ominous as our own, there were those who could see a way through the darkness to find a star to steer by. Carl Sagan wrote, “I was a child in a tim…