Rather than simply telling students the relationship between diameter and circumference, this lesson activity aims to have students experience it. It also places pi in the greater context of proportional thinking, and applies pi to a real world context with numeric and algebraic solutions. Includes pre-templated circles for students to use.
This is one of 12 lessons in my "In and Out" unit that targets area and volume for 7th graders in the advanced track. The goal of the unit is to build understanding of why the formulas for area and volume work, such that if students forget the formulas, they can cognitively reconstruct them on their own.