Because the diameter of a circle is related to the circumference of a circle, we can find this constant relationship by measuring several lids and fitting a regression line to the data. The slope of this line is pi. This is a great activity to allow students to discover that Pi is the relationship between the diameter of a circle and its circumference.
During the Activity
Read over the activity before beginning. Print out a copy of this activity for each student. This contains sample data and keystrokes for the calculator.