Celebrating Pi Day in my classroom hasn’t always been at the top of my list, and at times, I’ve not even been a fan of it at all (please don’t revoke my math teacher card!). Most of the time it just seems like a party day that, ultimately, ends up being a waste of time that I could’ve *really *used as an extra instructional day. That said, I love to celebrate and have fun as much as anyone, *and *I think community building is SUCH an important part of a creating a thriving math classroom culture, so I have definitely started to rethink my stance over the years.

I am not shy about saying I think there are some Pi Day activities out there that are a total waste of your time. If you’re honest with yourself about why you’re doing them, then you do you, but I knew that there had to be a better way to help students develop their love for math than just making paper chains.

A few years ago I decided to use Pi Day as an investigation day. The day has two main components:

- A
**circle investigation**where students will derive the formulas for the circumference and area of a circle. Seriously, how many of your students actually KNOW why C=2πr? I bet you they can sure as heck regurgitate it to you, though. This activity helps put context behind these formulas they’ve been using for years. - A
**coloring activity**where students calculate the area and circumference of circles. Each answer should show up twice, providing the color-coding key for the pi-day picture. No this isn’t the most rigorous thing, but it’s the reward for deriving the freaking formulas for circumference and area. They deserve a bit of color and chill time. And every age of student seems to love to color, it’s one of the universal truths of education. I’m telling you, from my freshmen to my seniors, they*love*coloring.

If you want to add in extra fun, you can give students a slice of pie as a reward for finishing the circle investigation. I’m cheap, so I’m not about to buy 20+ pies, but I’ve had coworkers who have incentivized students to bring in (storebought, of course) pies on Pi Day with small amounts of extra credit or a homework pass. If that’s something you’re interested in, I bet you can get creative.

First things first, let’s take a closer look at the circle investgation. It starts off by letting them discover what pi is, and then they derive the formulas for the circumference and area of a circle. My favorite part is the proof of the area formula for a circle…I think I have it laid out in a really cool way that is also very pattern-based for students. It also allows them to built upon their prior knowledge, which is fantastic! I also have some snazzy GIFs included, which (1) is just plain neat-o, and (2) really helps connect with your visual learners. QR codes are used so your students can pull up the GIFs to get hints and to check themselves.

For the record, all of my students already know the formulas for circumference and area, but I strongly doubt any of them actually know *why *those formulas work. Most of my students have been regurgitating those formulas for *years *without actually knowing one bit of the “why” behind why they work. So, from Algebra 1 to Pre-Calc, I think all of my students will really benefit from the conceptual understanding and process of deriving formulas that are introduced in this activity.

In the first investigation, students are to find and measure 5 circles using string and a yard/meter stick. I’m going to let my students go on a bit of a circle scavenger hunt around to school that way they’re not all using the same ones, but I also have 5 circles to print out for classes/students that I know might not be able to handle that amount of freedom. I plan to have my students work in groups of two or three. If you do decide to have them bring in pies, this would be a super fun option for them to measure all the pies (especially if they’re in varying sizes).

After students are done with the three parts of the investigation, they get to move onto the coloring activity to apply what they’ve learned. I don’t know what it is about coloring, but all of my students LOVE to do these types of activities. Regardless of age or gender, they are all down to color. This activity is also self-checking because of the way it’s set up. There are 10 problems in total that are broken up into two columns. Each of the answers from the first column will match up with another answer from the second column. The way that the problems match up creates the color-coding key for the picture.

I would love to know what you do in your class to celebrate Pi Day. Please leave a comment below, I’d love to hear from you!

-Audrey

If you would like to use these activities in your own class, you can find them **here**!