The end zone of a football field is 10 yards deep and 53 yards across. between the two end zones is the playing field, which is 100 yards long and 53 yards wide. what is the length of the diagonal from the back of one end zone to the back of the other?

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.

nkcoicjc