Pi Day!

Last week, we celebrated the most important holiday of the year: Pi day!

First, we had a full-school challenge to calculate the circumference of a large chalk circle outside. Several strategies were used: walking around the circle and measuring steps, estimating the radius with string length, even laying on the ground to use their height as a known constant. In the end, two groups ended up with the same, incredibly accurate answer, with 5 extra decimal points distinguishing the winner. All participants got starbursts, but the winners got to split a marionberry pie.

In 7th grade math class, our pi day explorations matched perfectly with the start of our unit on Proportional Functions. Writing out how to solve for the circumference of a circle, we realized that the equation was a proportional function! To investigate this function, we measured the circumference and diameter of several circular objects with string and rulers and plotted the points we found on a graph. The realization: We had graphed a line going through (0,0) with a slope of pi. This was the first proportional function they had ever graphed- a pretty great way to start out, in my opinion. During this exploration, we did stop to take class photos at 3/14 1:59:26 and then later at 3:14:15, clock included.

8th grade followed this with a breakdown of irrational numbers to more fully understand the nature of pi. Once we defined what irrational numbers looked like as decimals and (not as) fractions, we proved to ourselves that all repeating decimals can be written as fractions. Some students even justified to themselves the counterintuitive fact that .9 repeating is equivalent to 1! Understanding all the facets of rational numbers helps us know irrational numbers all the better.

(Personally, I prefer Tau as my circle constant, but I’ll let that get introduced alongside radians in High School).