This Instructional Activity is a part of the Lesson 1, Unit 8, Grade 8. In this activity, students use what they know about finding the area of a square from a given side length to think about the converse problem: how do you find the side length of a square with a given area? Students solve this problem in general in the next lesson, but this lesson sets them up for that work. First, they work with squares whose side lengths lie along grid lines, so both the side lengths and areas can be found simply by counting length or area units. They also see a "tilted" square whose area can be determined by counting square units or by decomposing and rearranging the square or a related figure.