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Question: Farmer Jones has recently brought a 40 acre field and wishes
to replace the fence surrounding it. Given that the field is square, what
length of fencing (in meters) should Farmer Jones purchase? Incidentally,
1 acre equals 43,560 square feet.
Answer: If 1 acre equals 43,560 and 1 ft equals
(see Tab. 2) then
Thus, the area of the field in mks units is
Now, a square field with sides of length has an area and a circumference .
Hence, . It follows that the length of the fence is