This Instructional Activity is a part of the Lesson 11, Unit 1, Grade 8. Sometimes people characterize congruence as "same size, same shape." The problem with this is that it isn't clear what we mean by "same shape." All of the figures in this activity have the same shape because they are all rectangles, but they are not all congruent. Students examine a set of rectangles and classify them according to their area and perimeter. Then they identify which ones are congruent.