Uhh, you keep flipping the yardstick on its end all the way down the field. I sincerely recommend using a tape measurer. If it is a football field, the lines are already there, so there would be no point in asking this question. If you are wondering weather or not there is a mathematical equation, no, there is not.
an Obisometer
You could measure a field by using tools such as a measuring tape or surveying equipment to calculate its length and width. Then, multiply the length by the width to determine the area of the field in square units.
Yards
The meter.
Metres
Usually, you would use kilometers.
Length would be the most appropriate unit of measurement
a big tape measure thing, I think they are used for construction, but I don't know the exact name for them
Metres.
the measure of a half of a football field
the measure of a half of a football field
Yards or Foot.