Once the octagon is created, the investigation can now focus on determining the segment lengths and the areas of the shapes. In one hand, hold up a 5½ × 5½ square, and in the other hand, hold up a completed octagon. Say to students, "The area of one of the original squares was 1 square unit. What is the area of the octagon that you just made?" Students should attempt to find the area of the octagon, possibly by finding the area of each of the eight congruent pentagons.