Sloped Surfaces and Area for Dummies

While most of the truly mind-numbingly dumb stuff on the internet hides in political arguments on social media, the Antisocial Network researchers generally stick to the insidious rubbish in the world of "how-to" and "informative" posts written by greedy people when looking for their DotD candidates. You know, instructions published by people who don't know how to carry them out, information cut-and-pasted by people who didn't know how to spell the topic before googling it, and so forth. Or, to be specific, the kind of mind-rot found published to eHow.com by one James Wiley in "How to Calculate the Area of a Sloped Surface" (now appearing at Hunker.com).

To be honest, we aren't really sure what the OQ meant. It probably meant something along the line of how to calculate the true area of a sloped surface seen in map view, which might be the tack that Wiley, a young Spanish-"global studies" grad, took:

"At first glance, calculating the area of a triangular, sloped surface seems like an extremely tricky task..."

...although we didn't see anyone mention "triangular" before this point; but if James actually did mean triangular, then his next sentence is off-point:

"...area is usually calculated by multiplying the length of an object by its width, but for a sloped surface one of those measurements is difficult to determine exactly, even with the help of a ruler or measuring tape..."

After all, the area of a triangle is one half base times height, not length times width. Whatever the case, it's apparent that Wiley thinks the answer is to determine the... "unsloped" length of a side which, as any thinking person can probably determine, is exactly wrong. Be that as it may, James approaches the task using the Pythagorean theorem. Sort of. According to Wiley, the steps are Measure the length of the sloped side of the surface as well as the other available side.  Square both the sloped side and the other side measured (either the length or the width).  Subtract the squared number of the width (or length) side from the squared number of the sloped side. Take the square root of the number, and you have determined the measured side. Now that you have both the length and width, multiply them to obtain the area of the sloped surface.

To which our staff geometry buff says, "WTF???" From his steps 1 and 2, it appears that he's trying to get the diagonal of a rectangle. Step 3-4, however, generate the third side of a right triangle that, if we're generous, has the sloped side of the area as its hypotenuse. After which point you simply calculate the area of a rectangle with one real side and one calculated side!

No, Wiley truly screwed this one up. If he wanted to calculate the length of the sloped side of a rectangle seen in map view, he needed to determine the elevation difference between the two ends and use that as the second side of a right triangle.  Then, of course, he could have just said (meeting the minimum word count, of course), "find the area of the map view and multiply it by the cosine of the slope angle," But, then, he'd have had to have known what "slope" and "cosine" mean...

Wiley's method, as written, is utter bull – and it's been out there on the internet for more than twelve years! Is it any wonder that our research team spends a lot of time looking at eHow and its contributors? No, it isn't -- because when you want another Dumbass of the Day like James, you go where the dumbasses are!

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