This document discusses calculating the circumference and area of a circle. It defines a circle as all points equidistant from a central point. The circumference formula is given as 2πr or πd. An example calculates the diameter of a circle given its circumference. The area formula is given as πr^2. Another example calculates the area of a circle given its diameter. Students are assigned to work in groups to create additional practice problems about circle circumference and area.