Mar 13, 2023

Pi Day Question of the Day: What pizza pie size did researchers find had the lowest price per sq. inch: 8-inch, 14-inch or 16-inch?

Which pizza pie would you choose on PI Day?

Answer: 16-inch pizza

Here's the ready-to-go slides for this Question of the Day that you can use in your classroom.


  • Now that you know that the 16-inch pizza is better value per square inch than the 8 or 14-inch pizza, would you plan to always buy it going forward? Why or why not?
  • Have you ever made pizza at home? How does the cost and value compare to buying pizza at a restaurant?
  • Bonus math question: What’s the formula for the area of a circle?

Behind the numbers (NPR):

The math of why bigger pizzas are such a good deal is simple: A pizza is a circle, and the area of a circle increases with the square of the radius. So, for example, a 16-inch pizza is actually four times as big as an 8-inch pizza. And when you look at thousands of pizza prices from around the U.S., you see that you almost always get a much, much better deal when you buy a bigger pizza.


Looking for another unit price activity? Look no further with this NGPF Data Crunch.


 Your class could win a bunch of 16-inch pizza pies with the FinCap Friday Frenzy contest. Find out the details



About the Author

Tim Ranzetta

Tim's saving habits started at seven when a neighbor with a broken hip gave him a dog walking job. Her recovery, which took almost a year, resulted in Tim getting to know the bank tellers quite well (and accumulating a savings account balance of over $300!). His recent entrepreneurial adventures have included driving a shredding truck, analyzing executive compensation packages for Fortune 500 companies and helping families make better college financing decisions. After volunteering in 2010 to create and teach a personal finance program at Eastside College Prep in East Palo Alto, Tim saw firsthand the impact of an engaging and activity-based curriculum, which inspired him to start a new non-profit, Next Gen Personal Finance.

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