Acreage for Utter Dummies

one acre compared to a football field

We were checking past award ceremonies the other day and found that the people at Leaf Group (whom we suspect of monitoring this site for useless posts in the eHow.com canon) had deleted a singularly stupid post by one Mallory Malesky, about measuring an acre. The old link redirects now to a post by someone named Paul Lin at GardenGuides.com, a post entitled "How to Calculate the Outside Perimeter of an Acre." Unfortunately, the replacement is no better than the original...

Lin, it appears, did not know the meaning of "acre." That's probably why Paul instructed his readers to

"Measure the perimeter of the acre with a distance measuring wheel. Plant the measuring wheel into [sic] the ground at one corner of the acre. Run the wheel along the outside edge of the acre until you hit another corner. Write down your measurement for the first side. Repeat this for the other three sides of your acre."

Which, of course, would be how to measure, not how to calculate. But wait – it gets worse. Lin's example is a rectangular "acre" with side measurements of 200 and 300 feet. We're here to tell you, that's not an acre. That's a plot of land that, technically, equates to 60,000 ft² or about 1.38 acres. Dummy.

An acre has, by definition, an area of 43,560 square feet. That means that if one side of the rectangular acre is 200 feet long, the other side must be 217.8 feet long. If the acre is a perfect square, then all sides must be approximately 208.7 feet long; yielding a perimeter of a tad under 835 feet.

The original definition of an acre, however, is a plot one furlong in length and one chain in width. Duh... OK, 660 feet long and 66 feet wide... so the "standard" acre has a perimeter of 1452 feet. Heck you could even have a circular acre with a perimeter (circumference) of about 740 feet (based on a radius of approximately 117.75 feet). One could, in fact, conceive of an acre with any shape... duh.

The circular acre has the smallest perimeter, while an acre one foot wide has the largest (87,122 feet). In other words, the question is nonsense unless the OQ supplied more information, such as the shape of the plot or some other qualifier – the "standard" acre or a square plot. No acre, however, is rectangular with sides of 200 and 300 feet. So now you know why Paul Lin is our Dumbass of the Day, right? Right.

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