This Instructional Activity is a part of the Lesson 6, Unit 7, Grade 7. The purpose of this activity is for students to see that sometimes it is impossible to build a polygon with certain conditions, but also that they need to think carefully about the information they are given before making assumptions. In this case, students are given 3 side lengths that cannot form a triangle and are told to build a polygon. Students may assume that because they were given 3 side lengths, their shape is supposed to be a triangle; however, they will only succeed in building a polygon using the specified side lengths if it has more than 3 sides. Formalizing rules about what lengths can and cannot be used to form a triangle is not the goal of this activity.