Discovering Pi/Welcome to Pi Day

High schoolers explore pi. In this circle measurement instructional activity, students define and identify radius, diameter, circumference, and perimeter. High schoolers work in groups to measure several plastic lids and record their findings. Students compare the relationship between the diameter and radius, then complete a "Circumference vs. Diameter" worksheet. High schoolers explain the circumference formula based on their measurement comparisons. Worksheets and information about "Pi Day" are included.