Area

How much space does this board take up? 🤔

👉 To figure that out, let's find the board's **area!**

**Area **is the amount of space a **flat **shape or surface takes up.

**Tip:** Only two-dimensional objects have an area. Three-dimensional objects have **volume**.

The **cover of a book** is flat. The **front of a closet door** is flat.

Let's find the area of a **grid** like this board

One way to find theareaof a grid is tocountall the squares in it.

Let's count them now.

How many squares are there?

That's right! There are 30 squares.

😀 The area of the board is **30 square units**.

**1 square **is **1 square unit**.

But counting is pretty slow. Let's learn a faster way.

To find the area of a **grid **like a rectangle or a square, just **multiply the height **times the **width**.

HeightxWidth= Area

Why does this work? 🤔

Because **grids **are just columns **multiplied**** **by some number of rows! 🤓

How many rows and columns does our grid have?

Now what happens when we multiply the number of rows (5) times the columns (6)?

5x6=30

We get the same answer from multiplying as we do from adding all of the squares!

😺So remember:

**Multiply **the **length **and **width **of any rectangle or square to get its **area **quickly.

Just like length, weight and time, **area **also has some **units of measurement**.

** Units of area **tell us how big or small an area actually is.

Imagine that this is the measurement of each square on the board.

We see that the square is 1 centimeter (cm) long. This is its **length**.

The square is also 1 centimeter (cm) wide. This is its **width**.

👉The area of a square 1 cm wide, and 1 cm tall is **1 square centimeter.**

**Square centimeter **is a unit of measurement for area. It's written as **cm²**.

In the United States, people also use **square inches **as a unit of measurement! It's written as **sq.in. **or **in²**.

👉The **area **of a square 1 in wide, and 1 in tall is **1 square inch.**

So, what's the area of our board?

We know that it's 30 square units.

If the area of each square is 1 cm² , then the **area **of the board is** 30 cm².**👍

What if we want to measure the area of larger spaces, like this field of grass?

What unit of measurement should we use? 🤔

😌 Square centimeter would be too small.

For larger spaces, the unit of measurement often used is **square meter.** It's written as **m²**.

When our **unit of area **is the **square meter**, it means that the area of each square is **1 m²**. 👍

In other words, the length of each square unit is 1 meter and its width is also 1 meter. 👍

Now, let's measure the area of the yard.

👉 A** grid **can help us count the square units.

Each square unit has an area of 1 m².

How many square units cover the inside of the yard?

You can figure out by counting the squares, but that would take a long time.

Let's **multiply** the columns by the rows instead.

5 x 9 = ?

What do we get? **45 square units**!

So, the area of the yard is **45 m²**.** **🎉

In the United States, people often use **square feet **instead of **square meters**!

1 **square foot **is the area of a 1 ft by 1 ft square. It's abbreviated as **sq. ft. or ft²**.

Square feet are smaller than square meters.

1 m^{2} can fit over 10 ft².

It's easy to find the area of a grid. We just count the squares inside, or **multiply** the length times the width.

🤔 But what if you want to estimate the area of an irregular surface, like this red eraser?

👉 First, **count all the ****full squares **inside the eraser.

There's only one - the blue square. It's area is 1 m².

👉 For the other squares use this estimation rule:

- If the eraser covers **more than half of it**, count it as **1 m²**.

- If the eraser covers **less than half the grid**, count it as **0**.

Look at squares 1, 3, 4, and 6:

Each of these squares covers more than half of one square. So, their total area is 4 m².

Look at squares 2, 5, and 7:

Each of them cover less than half a square. So, their total area is 0.

👉 We bring the three totals together.

1 + 4 + 0 = 5 square meters

The **estimated area** of the eraser is 5 m²**. **

Great work! 🎉

Now, you can try the practice exercises. 💪

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