ANSWER
100 yards.
EXPLANATION
The length of the rectangular field is 80 yards.
The width of the rectangular field is 60 yards.
We use the Pythagoras Theorem to find the length of the diagonals, d.
[tex] {d}^{2} = {w}^{2} + {l}^{2} [/tex]
Put the values of the length and width of the rectangular field into the formula.
[tex] {d}^{2} = {80}^{2} + {60}^{2} [/tex]
[tex] {d}^{2} = 6400 + 3600[/tex]
[tex] {d}^{2} = 10000[/tex]
Take the positive square root of both sides.
[tex]d = \sqrt{10000} [/tex]
[tex]d = 100[/tex]
The diagonal of the rectangular field is 100 yards.
