When you put the pieces of the field together, you have a rectangle that's 53 yards
wide and 120 yards long.
When you draw the diagonal, it divides the field into two right triangles.Each one
has legs with lengths of 120 yards and 53 yards. The diagonal of the field is the
hypotenuse of both right triangles.
(120)² + (53)² = (the hypotenuse)²
14,400 + 2,809 = (the hypotenuse)²
17,209 = (the hypotenuse)²
The diagonal (hypotenuse) = √17,209 = 131.183... yards (rounded)
I guess that's the longest straight line it is possible to run on a football field
while staying in bounds.
