To find the area of a square garden, we first need to determine the length of one side of the square using the perimeter.
The formula for the perimeter \( P \) of a square is given by: \[ P = 4s \] where \( s \) is the length of one side.
Given that the perimeter is 60 m, we can set up the equation: \[ 4s = 60 \]
To find \( s \), we divide both sides by 4: \[ s = \frac{60}{4} = 15 \text{ m} \]
Now that we have the length of one side, we can calculate the area \( A \) of the square using the formula: \[ A = s^2 \] Substituting \( s \) into the area formula: \[ A = 15^2 = 225 \text{ m}^2 \]
Therefore, the area of the square garden is \( \boxed{225} \) square meters.