Any angle can be accomplished when throwing a football with practice. Take a rope and place it where you threw the football. Then stretch it down to where the football lands. Then measure the rope.
A tape measure.
A tape measure.
Take a tape measure and measure the distance around the football at the center. Then, take that number and divide it by 3.14, then divide that by 2.
A centimetre.
use inches
an Obisometer
Football fields
on the foot ball field
Metres, to measure its length or width, square metres to measure its area.
The only reason that I can think of is that you want to communicate with a person who is not familiar with the English system - football rules measure the field in yards or feet, so square meters is an unnatural measure for them.
In English football pitches are not all the same size. They have to measure between 90m and 120m long and between 45m and 90m wide. If you mean US football I don't know.