We celebrated March 14, or Pi Day, a little early at Vacaville’s Imagine That so that our students would know a little about pi for this weekend. Pi is an important number in geometry, used in calculating the area and perimeter of a circle. Pi is a number that never ends, but as the first 3 digits are 3.14, every March 14 is Pi Day. Some mathematicians like to argue we should celebrate Tau Day as well, which is double pi, but there are no tasty treats associated with the word Tau, so it just hasn’t gained popularity.

We ordered tarts, or mini pis, for one of our challenges, which had our students dividing the pies into halves, quarters, and eighths to help introduce or refresh their knowledge of fractions. We ordered 40 pies for our 30 students, so we had some of the older students try to calculate how to divide the pies equally among the students. We asked if they could find or make two circles, one with a diameter equal to the other’s radius, which meant we introduced those terms. We also talked how pi is used to calculate area and perimeter, which means we talked about those terms as well. Some of our students have recently been calculating the area of a rectangle, so we asked how a circle would be different. They asked why people would need to know about the area of a circle, so we introduced some of the reasons they would have used pi in the ancient world, such as in building architecture.

Another practical application for pi was provided by NASA. NASA issues a Pi Day challenge for students in 4-12 grade. This is a little above most of our students, but we shared the easiest of the challenges. This challenge presented the students with the challenge of gathering samples from an asteroid. Each circular pad collects samples based on its surface area. If they needed a certain amount of sample, how many pads would they need?

Finally, for a bit of art fun, we created a Pi Skyline. We used some graph paper to draw out the first 20+ digits of pi along the bottom. Some of the students created a sky in the background, creating a cityscape.