This math topic focuses on determining the length of line segments drawn on a grid comprising 1x1 squares. It forms part of an introductory perimeter unit and introduces learners to the concept of measuring and identifying line segments of specific lengths on a grid. The problems provide visual references and require students to select the correct line segment corresponding to given lengths, such as 9, 10, 11, 12, 13, 14, and 15 units. This task develops spatial reasoning skills and foundational knowledge needed to understand perimeter.