The purpose of this activity is for students to find the length of a missing side of a shape when the perimeter is given, using any strategy that makes sense to them. The Activity Synthesis highlights the variety of methods students used to solve the problem.

• Select previously identified students to share their strategies. Be sure to share at least one method (more if possible) for each problem.
• Consider asking:
  • “When would this strategy be most useful?”
  • “Did anyone think about it in a different way?”

The purpose of this activity is for students to solve problems in situations that involve perimeter (MP2). Students may draw diagrams with length labels or simply reason arithmetically. They also explain how each problem does or does not involve perimeter. The Activity Synthesis provides an opportunity to begin discussing the difference between area and perimeter, which will be fully explored in upcoming lessons.

• “What is the problem about?”
• “How could you represent the problem?”

• Select previously identified students to share their reasoning for each problem. After each problem, consider asking: “Did anyone solve this problem in a different way?”
• If possible, keep the student work displayed for the Lesson Synthesis.