# How big are pizzas?

Is a 12-inch pizza twice as big as a 6-inch pizza?

Simply put, no. The amount of pizza (its area) is proportional to the square of its diameter, so a 12-inch pizza is actually four times bigger than a 6-inch one.

Looking at the cost per square inch shows an interesting pattern: as size increases, the cost per square inch goes down. (Data from Dominos Pizza.)

If we take the trend that the data is following and solve the equation of the trendline (line of best fit) then we find two possible solutions: the cost per square inch falls to £0.00 at a diameter of either −128 inches or 22 inches. Since a pizza with a diameter of negative 128 inches is clearly ridiculous, it’s the free 22-inch pizza that is interesting.

## 6 thoughts on “How big are pizzas?”

1. I’m going to write a piece about this on AOL Money but I’d love to speak to you first, if you are around. You have my email address. I can phone you.

2. Crimeboy says:

Unexpurgated trumpery moonshine. By the logic of this fellow, a pizza of diameter zero, or in other words, no pizza at all would be 27p a square inch. He also fails to mention that, according to his graph, if the pizza were to exceed 22 inches, the vendor would have to pay you to accept the pizza from them…There must be number-crunchers with the craft of Mr Reid employed by the government, given the nonsensical statistics we are expected to digest.

3. I think you’re taking this a little bit too seriously …

4. Alun says:

Crimeboy is missing something: 27p * 0 = 0p. You don’t have to pay for no Pizza at all. This also explains exactly why Dominos refused to make a 22inch Pizza the other day :)

Han on, a pizza with negative radius still has a positive area…. Calzone?