What is the perimeter of a square with side length 9?

To find the perimeter of a square, you use the formula ( P = 4s ), where ( P ) is the perimeter and ( s ) is the length of one side of the square. In this case, the side length is given as 9.

By substituting the value into the formula, you perform the calculation as follows:

( P = 4 \times 9 )

This simplifies to:

( P = 36 )

Thus, the perimeter of the square with a side length of 9 is indeed 36. This makes the correct answer consistent with the formula for determining the perimeter of a square, confirming its validity within the context of the geometry involved.