Answer:
(200π - 12)ft
or
616.32 ft
Step-by-step explanation:
Given in the question,
there are four circle around which corn will be planted.
radius of first circle = 10 ft
radius of second circle = 20 ft
radius of third circle = 30 ft
radius of fourth circle = 40ft
circumference = 2πr
First circle
2π(10)-3
20π -3
Second circle
2π(20)-3
40π-3
Third circle
2π(30)-3
60π-3
Fourth circle
2π(40)-3
80π-3
Add them up
80π - 3 + 60π - 3 + 40π - 3 + 20π - 3
(200π - 12)ft
or
616.32 ft