If there are 2 end zones each measuring 10 yards long then that means that both together measure 20 yards long. We add this to the 100 yards of the field and we get a total length of 120 yards. Now we can simply turn this into feet, we know that ...
1 yard = 3 feet
120 yards = x feet
120 * 3 = x
360 feet = x
Finally, we can see that the length of the football field is 360 feet.
