This Instructional Activity is a part of the Lesson 4, Unit 3, Grade 7. In this activity, students compute the length of a figure that is composed of half-circles and straight line segments. For the first question, they are given the length of the line segments and the diameter of the circle. For the second question, students have to compute the diameter of the circle. As students work, monitor for students who decomposed the figure in different ways and used different approximations of pi.