Square perimeter 36, find the side

Step by step

The question

Question: find the side s of a square with perimeter 36.

1 Write the rule

All four sides of a square are the same.

So the perimeter is 4 times the side.

So 4 × s = 36.

Careful!

The square root is for the area.

The perimeter is 4 sides added, so we divide by 4.

2 Remove the × 4

We want s by itself.

The times 4 is in the way.

To remove times 4, we divide by 4.

We do it on both sides.

Why both sides?

The = sign means both sides are the same amount.

If we change only one side, they are not the same any more.

4 divided by 4 is 1.

So just s is left.

36 divided by 4 is 9.

So the side is 9.

3 Check

Let's check: 4 times the side.

We get 36, the perimeter.

So the side is right!

Let's look back.

First: write the rule.

Then: remove the × 4.

Last: check.