The perimeter of a square is the distance around it. There are four equal sides to a square. Therefore, if one of its sides is \(s\), and perimeter is the sum of all sides, we have \(s+s+s+s\) or simply \(4s\).

**Example 1:** What is the perimeter of a square with a side length of \(5\) feet?

Since the side is \(5\), we let \(s=5\). The formula of the perimeter of square is \(4s\), therefore \(4(5)=20\) feet.

**Example 2:** If the perimeter of the square is \(28\) meters, how long is the side?

The perimeter is \(28\) which means \(P=28\). Since the formula is \(P=4s\), we can substitute \(P=28\) then solve for \(s\).

$$\eqalign{

P &= 4s \cr

28 &= 4s \cr

{{28} \over 4} &= {{4s} \over 4} \cr

7 &= s \cr} $$

Therefore, the side of the square is \(7\) meters.