Area of circle radius 7 cm

Step by step

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.