Peter is making an "X marks the spot" flag for a treasure hunt. The flag is made of a square white flag with sides of 121212 centimeters. He will make the "X" by stretching red ribbon diagonally from corner to corner.

How many centimeters of ribbon will Peter need to make the "X"?
Round your answer to the nearest centimeter.

To find the length of the diagonal ribbon required to make the "X" on the square flag, we can use the Pythagorean theorem, which states that the square of the length of the hypotenuse (the diagonal in this case) is equal to the sum of the squares of the other two sides (the sides of the square flag in this case).

So, for a square flag with sides of 12 centimeters, the length of the diagonal can be found as follows:

Length of diagonal = √(12^2 + 12^2) = √(144 + 144) = √288 ≈ 16.97 centimeters

Therefore, Peter will need approximately 17 centimeters of red ribbon to make the "X" on the flag.