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### Course: 3rd grade (Eureka Math/EngageNY) > Unit 4

Lesson 2: Topic B: Concepts of area measurement- Area of rectangles with partial arrays
- Counting unit squares to find area formula
- Create rectangles with a given area
- Transitioning from unit squares to area formula
- Transition from unit squares to area formula
- Area of rectangles
- Find a missing side length when given area
- Finding missing side when given area
- Area of rectangles review

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# Area of rectangles review

Review the basics of area of rectangles and try some practice problems.

## What is area?

**Area**is the space inside of a two-dimensional shape. We can also think of area as the amount of space a shape covers.

For example, the rectangle below has an area of $12$ square units because it $12$ square units.

*covers**Want to learn more about the concept of area? Check out this video.*

## Area of a rectangle formula

To find the area of a rectangle, we multiply the length of the rectangle by the width of the rectangle.

*Want to know why this formula works? Check out this video.*

### Example 1:

### Example 2:

### Practice set 1: Multiply to find area

### Practice set 2: Count square units to find area

*Want to try some more unit square problems? Check out these exercises:*

Find area by counting unit squares

Transition from unit squares to area formula

Create rectangles with a given area

### Practice set 3: Challenge items

*Want to try some more challenge items? Check out these exercises:*

Find a missing side length when given area

Decompose figures to find area 1

Decompose figures to find area 2

## Want to join the conversation?

- How do you figure out square feet? I need to calculate the area of a back splash so i can purchase wall tiles.(31 votes)
- for tiles times the length by the width and you get the area(16 votes)

- If a shape is uneven, how can we work out the area?(11 votes)
- Try to break the shape into simpler shapes - ones that have areas that are easy to calculate. Calculate the area of each smaller shape, then add them all together to get the area of the whole shape.

(*This is what they did up above when they had us count squares to figure out the area of the big shape.*)

Each square is 1x1, so the area of each square is one.

(*First step: calculating the area of the smaller shapes.*)

Then when we counted all the squares, the total number of squares was also the area of the shape.

(*Second step: add together all the areas of the smaller shapes.*)

Hope this helps!(26 votes)

- how do you find area of a 3D shape? is it multiplying 2D shapes? why does time pass in different time zones? how does an earthquake cause a tsunami? also, force can move things right? how can a smaller amount of force move a big object?(17 votes)
- time passes in different time zones cause of the way the earth is facing the sun(11 votes)

- what if you reverse the numbers of the area would the answers still be the same?🤔(11 votes)
- It would! For a rectangle, it doesn't really matter which side is length and which side is width. Because the order in which you multiply two numbers doesn't matter, the area is the same both ways. You can think of just turning a rectangle from the skinny side being horizontal to it being vertical. Nothing changes about the amount of space the rectangle takes up, so its area is the same :)(12 votes)

- this is a good practice but a bit tricky(15 votes)
- It is 7 times 8 equals 56(14 votes)
- whats the first answer for the frist one(11 votes)
- length x width(5 votes)

- Just so you all now I saw that many of you are saying how hard this is, but I have good news! If you know your multiplication chart (or at least some of it) this is easy. I at the beging thought this was hard but as I gave myself to and it its a little easy. And this is coming from someone who isn't that great at math. Hope this helps you all! If you all were helped by this please upvote. :)(12 votes)
- I don't have any but i like doing this it was fun.(10 votes)
- How do you figure out the wigth day dividing?(9 votes)