61/100 = 0.61
so
the least is 61/100 then 0.65 and then 61.5 last
It is in the air 5.625 seconds.
Using the quadratic formula,

0 is when the ball is first launched, 5.625 is when it hits the ground again.
(50 x 2) + (40 x 2) = 180 yards x 3 = 540 feet of fence needed. 540 / 5 = 108. He will need 108 pieces of fencing