In this lesson, students apply the relationships between diameter, radius, and circumference to solve problems in a variety of contexts. Students develop flexibility with using the relationships rather than memorizing a variety of formulas. Understanding the equation will help with the transition to the study of area in future lessons.

Next, students solve problems about distances of paths composed of multiple circles or parts of circles and other shapes. They think strategically about how to decompose and recompose complex shapes (MP1) and need to choose an appropriate level of precision for and for their final calculations (MP6).

The last activity is optional because it provides an additional opportunity to apply circumference to solve a problem that requires composing and decomposing parts of circles.