Oh FFS. This simple question has apparently caused all sorts of mayhem among the innumerate:

The answer is of course “FALSE” — and to think otherwise is to be ignorant of two of the simplest definitions in mathematics, i.e.

- “A right angle is defined as two straight lines meeting at a 90-degree angle”,
**and** - “There are no straight lines in the circumference of a circle.”

And in the above picture, there’s only one straight line.

That anyone can even be fooled by the question means that math education has been completely screwed up. I agree that it’s quite a tough question for a seven-year-old child (as posed in the article), but nobody with more than a seventh-grade education should be stumped by it, let alone **a professor of mathematics**.

By the way, ignore the red herring that a straight line consists of two right angles: that’s only a **partial** definition of straight line. (“The shortest linear distance between two points” contains only **implied** angles, not actual ones.)

And by the way: the correct **spelling** is “two right angles”, no hyphen necessary.

I need another gin.

Update: Oh FFS-squared.

For the above diagram to contain two right angles, one would have to add a third radius, thus:

Now the question “There are two right angles” has the answer “True” (A0C, B0C). If you were to answer “False”, giving “because there are **four** right angles” as your reasoning, you would (rightly) be given an “Incorrect” because there are only four right angles in the **imaginary** world (i.e. Thales’ Theorem *et al*.). However, we are not in an imaginary world because we are not talking concepts, we are talking about an actual diagram. And to cap it all, we are talking about a question posed to **a seven-year-old child,** for whom Thales has no existence.

As I explained to a Reader in an email on this very topic, it always pays to remember that mathematics has little basis in reality, e.g. where a line can have direction but no thickness and a point has a position but no size. And I’m not even going to touch on division by zero… *[eyecross]*