Area of rectangle 8 by 5 Easy

The question

Question: find the area of a rectangle 8 long and 5 wide.

1 What area means

Area is how much space is inside.

We count the 1 by 1 squares that fit.

One row has 8 squares.

There are 5 rows.

2 Length times width

So the area is length times width: A = length × width.

Squares in a row, times the rows.

Now put the numbers in: length = 8 and width = 5.

8 times 5 is 40.

So the area is 40 square units.

3 Check

Let's check: count row by row.

5 rows of 8 squares.

We get 40 again.

So the area is right!

Let's look back.

First: what area means.

Then: length times width.

Last: check.

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Area of circle radius 3 Medium

The question

Question: find the area of a circle with radius 3.

1 Use the rule

π is a special number for circles.

It is about 3.14.

The area of a circle is π times the radius squared: A = π × r².

So we write A = π × r².

Now put the numbers in: r = 3.

3² means 3 times 3.

That is 9.

So A = π × 9.

We write it as 9π.

We keep π in the answer.

That is the exact answer.

2 About how much

To see about how much, put 3.14 for π.

9 times 3.14 is 28.26.

So the area is about 28.26 square units.

Let's look back.

First: use the rule.

Last: about how much.

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Area of circle radius 7 cm Harder

The question

Question: find the area of a circle with radius 7 cm.

1 Use the rule

π is a special number for circles.

It is about 3.14.

The area of a circle is π times the radius squared: A = π × r².

So we write A = π × r².

Now put the numbers in: r = 7.

7² means 7 times 7.

That is 49.

So A = π × 49.

We write it as 49π.

We keep π in the answer.

That is the exact answer.

2 About how much

To see about how much, put 3.14 for π.

49 times 3.14 is 153.86.

So the area is about 153.86 cm².

Let's look back.

First: use the rule.

Last: about how much.

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