Pizza is a Triangle (and other lies we tell children)

Sorry to break it to you Will but pizza boxes aren’t squares, pizzas aren’t circles, and a slice of pizza is most definitely NOT a triangle.

Did you like Geometry? You probably remember it as a subject in high school but did you know that geometric concepts begin at birth? Infants begin to notice shapes in their environment as soon as they can see and by the time they are 18 months old they are able to match basic shapes, even if they aren’t talking yet!

But we don’t need to go that far back. I’m sure you learned your shapes in kindergarten. Something like this:

Seems simple, right? Watch Sesame Street, color in a few worksheets and you have all you need to know. Until, that is, you are asked to write proofs in high school Geometry. Maybe you remember writing proofs as a high school student. Or, maybe you are like me and have no idea if you even attempted it. Either way, I’ll bet that up until that point you had never been asked to justify your thinking in math, never had to prove why a square is a square… or even question it! If this seems familiar, keep reading.

PSA- IF YOU KNOW OR EVER WILL KNOW A YOUNG CHILD: Please be aware that elementary school students will be expected to not only name shapes, but also define, compare, classify, sort, compose, decompose… oh, and prove and justify their reasoning. This may be difficult because there are a number of lies about geometry that students need to unlearn (see below) but relax. All children are capable of these things when given the opportunity to do so.


Lie #1: Pizza is a triangle

Truth: A triangle is 2 dimensional (length and width = two dimensions). Pizza is just delicious. Triangles are FLAT (no, thin crust doesn’t count).

Lie # 2: A rectangle has two short sides and two long sides


Truth: It might… but it might also have 4 sides that are all the same length. In that case it is a SQUARE rectangle. That’s right folks, a square is a rectangle with a special name (a square is also a rhombus, paralellogram, and quadrilateral… don’t trust a square).

Lie #3: Diamond is a shape (despite what all the children’s books say)

Truth: According to Britannca, a diamond is “a mineral made of pure carbon”. Not a shape. The RHOMBUS might look like a diamond to some but I don’t see the resemblance.

The lies do not stop there, but I will.

Now, go find all the children’s books about shapes and cross out diamond and write rhombus (use Sharpie).


PS- None of these are triangles

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