Main content

## 3rd grade

### Unit 10: Lesson 2

Count unit squares to find area- Intro to area and unit squares
- Measuring rectangles with different unit squares
- Find area by counting unit squares
- Compare area with unit squares
- Creating rectangles with a given area 1
- Creating rectangles with a given area 2
- Create rectangles with a given area

© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice

# Measuring rectangles with different unit squares

Sal finds area of a rectangle with different sized units. Created by Sal Khan.

## Want to join the conversation?

- So, can you just use all six of the mini units that are 1 square foot and make a big square and do it the same for the other side? It will have the same amount of space, but different areas. Can we do that if it is possible?(8 votes)
- yes you can ,but both will have the same area because it has the same amount of space the only difference is that they will be measured in different square units

for example the measure of a square, measured in mm will be the same as measure in cm just that there will be a difference in number because u r using 2 different units but when u convert the answer u get in cm to mm the area will be the same

hope this helped(6 votes)

- at2:15what is a furgle(1 vote)
- A
**furgle**is a made-up unit of measurement.

1 furgle = 2 feet

At2:23, Sal comments that "one furgle" is something that he made up just for this video, so that we can practice measuring identical rectangles with two*different*units: feet & furgles.(13 votes)

- A rectangle has an area of 18"and the height of the rectangle is 6 inches what is the length of the rectangle(5 votes)
- Remember that the area of a rectangle is its length x its height. So, we know the formula is (l x h = a).

Let's plug in our known values: (l x 6 = 18)

Let's rearrange to isolate the variable: (18 / 6 = l)

Let's solve for the length: (l = 3)

So, the length of the rectangle is 3 inches. It's simple algebra! Let me know if you have further questions.(2 votes)

- What is a "voot" as used in the video at @0:58seconds?(5 votes)
- how does area help the real world(3 votes)
- It helps in panting spaces in a lot or planting seeds,and placing tiles in your house.(4 votes)

- What is a furgle(3 votes)
- A furgle is a made-up unit of measurement.

1 furgle = 2 feet

At2:23, Sal comments that "one furgle" is something that he made up just for this video, so that we can practice measuring identical rectangles with two different units: feet & furgles.(5 votes)

- At2:02what is a feet? And why does it sound weird?(3 votes)
- It sounds weird because Sal is actually saying 'veet' and not 'feet.' Presumably 'veet' is the plural form of 'voot.' Sal is comparing feet and veet (a fictional unit) to show how we can use different units of area to measure the same object, but we have to take into account that the units are not of equal size.(4 votes)

- maybe why its so we can doit beter and take notes(3 votes)
- at3:19does it have to be square?(2 votes)
- i guess so :)(2 votes)

- it was last talking about area. area is the space in a shape it takes up.(2 votes)

## Video transcript

- What we're going to do in this video is look at two rectangles
that have the exact same area, and we're going to measure each of them with a different square unit. So this top unit right over
here, this is a square foot. So that means its height is one foot and it's width right here is one foot. Now, this is square unit over here, this is completely made up. And I'm going to call
this a voot or a voot. So, this right over here is one voot and this over here,
the width, is one voot. So this entire thing is a one square voot, while this top one, of
course, is one square voot. Now, let's measure the top rectangle in terms of square feet, and let's measure the bottom
rectangle in terms of square, I guess I could say veet,
(chuckles) all right. So first the top rectangle. So we have one, two square feet, three square feet, four square feet, five square feet, and then we have, looks
like six square feet. And then we're gonna need to
have another six square feet down here. So that's seven, eight,
nine, 10, 11, and 12. So when I tile these square feet onto our original rectangle, it looks like we have 12 square feet. And so I could write it's area
like this, 12 square feet. Now what about this one in terms of veet? You could have a square
voot or many square veet. Let me do the same exercise here. That's one square voot, this is two square veet, I could say, and then this is three square veet. So the same area could
either be 12 square feet or it could be three square veet. And I want you to think about
whether that makes sense. Think about how many square feet would make up one square voot. In fact, we can figure that
out on our own right over here. So that's one square foot,
this is two square feet, this is three square feet,
and then four square feet. So it looks like four square
feet make up one square voot. And so think about, does it make sense that three square veet is the same thing as 12 square feet?