I have two responses for you.
George,
An acre is a unit of area, it is 43560 square feet, but it can be any shape, a square, a circle, a long thin rectangle, a triangle, pie shaped or any other shape.
 If it is a square, the sides would be approximately 209 fet long and you would need 4 209 = 836 feet of fencing.
 If it is a circle then the perimeter is 740 feet
 If it is 100 feet wide then it is 436 feet long and the perimeter is 1072 feet.
The perimeter depends on the shape as well as the area, so without knowing the shape you can't find the perimeter.
Penny
Hi George.
Perhaps the reason you are exhausting all your resources is that there is no one right answer to your question. Acres are a measurement of area and that doesn't tell you enough to know the shape and size of the perimeter.
Think about it this way. If you have 4 square feet of area, that could be a 2 feet by two feet square. The perimeter is 4 x 2 = 8 feet. But what if that 4 square feet was in the form of a rectangle 1 foot by 4 feet? Then the perimeter is 1+1+4+4=10 feet.
You question has the same problem. In fact, if the land is not square or rectangular, you can still have an area of one acre and a perimeter to figure out. For example, a circular lot of land that is one acre in size would have a perimeter of 740 feet.
Stephen La Rocque.>
