Ovals for Dummies

Ellipse semimajor (A) and semiminor (B) axes

We haven't done the math, so to speak, but off the top of our collective head the geometric figure our DotDs have the most problems with is something called an "oval." At least twice, we've featured freelancers who have tried to tell readers how to calculate something about an "oval" and once we had some putz who tried to describe how to draw one. Bummer, eh? Especially, given that an oval – unlike an ellipse – has no fixed definition. That didn't stop Leaf Group rewrite specialist Claire Gillespie, though, when she took on "How to Calculate the Circumference of an Oval."

Gillespie's not the first to tackle this assignment. The original post, which dated back to 2010, was written by five-time awardee Mark Kennan; then rewritten by Bryan Grubbs. Gillespie's take is heavily influenced by the work of Grubbs, an English Comp major – especially her inclusion of a common error Bryan made. But first, let's see how Claire gets around the definition of an oval. If you were to look the word "oval" up at Wikipedia, you'd learn that,

"The term oval when used to describe curves in geometry is not well-defined..."

In other words, when Gillespie solemnly intones that,

"An oval looks like an elongated circle and is most commonly called an ellipse in geometry..."

...she's blowing smoke up your skirt. Kennan (sometimes known as Keenan) didn't even bother with the ambiguity of "oval," he went straight to calculating. It was Grubbs who said,

"An oval is like an elongated circle, and mathematicians often call it an ellipse. "

Well, no, Bryan and Claire, mathematicians don't think an oval and ellipse are the same thing; that's apparently the opinion of English comp and journalism graduates. That over-generalization is not, however, the most serious error propounded by Grubbs-Gillespie. No, that bit of stupidification goes something like this:

"The major axis spans the length of the ellipse, running through the center and connecting the two farthest points, while the minor axis sits perpendicular to the major axis and connects the two closest points."

No, people, the minor axis does not connect "the two closest points"! The minor axis connects the two points farthest apart on a line perpendicular to the major axis; it is sometimes known as the "shortest diameter." Gillespie then goes on to tell her readers to,

"Note the major and minor axes of your ellipse and find the exponent of both."

Say WHAT??? This moron thinks that multiplying a number by itself yields the number's "exponent"??? Even Grubbs knew this is the "square" ["quotation marks" Grubbs'] of the number. Gillespie further insults mathematics with the claim that,

"The value of π... is always 3.142"!

That's an assertion that will surprise a lot of people. At least she didn't say it is always 22/7... Even worse, Claire claims that the formula for the (approximate) circumference of an ellipse is, "C = 2 x π x √((a2 + b2) ÷ 2)" Again: wait, what? "a2 + b2"? This from the freelancer who doesn't know what an exponent is? No, Claire, the term is "a² + b²"! Even worse, a and b are the semimajor and semiminor axes of the ellipse, not the major and minor axes. In other words, Claire's example calculation (major axis = 12, minor axis = 8) is off by a factor of two!

Sheesh: failure to understand the difference between "square" and exponent... incorrect transcription of a formula... failure to understand the significance of the prefix "semi-"... conflation of an oval with an ellipse. What did we miss? Giving Gillespie the Dumbass of the Day award, we guess.

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