We are given that the perimeter of a square is 68. Since the perimeter of a figure is the sum of all of its sides then the formula for the perimeter of a square is:
Where "l" is the length of its sides. We can solve for "l" by dividing both sides by 4:
Replacing the value of the perimeter:
Now, the length of the diagonal of a square is:
Replacing the value of "l":
Solving the operations:
Therefore, the length of the diagonal is 24 feet.