Cake math

Hit and Miss #412

Say it’s Friday after a long week, a week that was more of a rollercoaster than you’d anticipated1, and a Friday that itself had some unexpected twists to it. You’re driving home after picking up some medication from the vet (or some other similarly “oh yes, the realities of life” type errand), and passing a Dairy Queen.

Because you’re an adult who knows when you need to treat yourself, it’s a no-brainer to hang a right and pull in. The $6-off coupon your driving companion brandishes doesn’t hurt, either.

This coupon, though, it’s only for a purchase over $30. Which brings you, inevitably, to the ice cream cake section of the store.

Now, a wave of responsibility may wash over you. You may think to yourself, “Okay, getting an ice cream cake on the spur of the moment—this feels a bit indulgent. So we should just get a small one.”

For good reason, you should push through that wave.

Small ice cream cakes at DQ are 8 inches diameter. The next size up is 10 inches. The price difference is small, less than a 10% increase from the 8-inch to 10-inch cake.

Because of the beauty of cake math (or, for the less sugar inclined, “geometry of circles”—this applies to pizza and other round delights!), that 2-inch increase in diameter is not a mere 25% increase in the amount of cake you’re getting—it’s a more than 50% increase. (To compare the size of two cakes, use r^2, where r is the radius, or half the diameter, of your cake.)

So for less than 10% more in price, you’re getting more than 50% more in cake. Indulgent, sure, but it’s economically efficient indulgence—and all the sweeter for it.





All the best for the week ahead! Eat some cake, and be logical about which size you pick!

Lucas

  1. The Hockey Canada verdict landed right as Arthur was going through a flare-up. The outcome wasn’t a huge surprise, which just underlines the problem. Thursday was a hard day.