This topic focuses on practicing the measurement of line lengths on a grid composed of 1x1 squares. It requires identifying lines of specific lengths, specifically 3, 4, and 5 units. This is part of an introductory lesson on the perimeter, enhancing understanding of basic geometry and measurement skills by using grids to visualize and solve problems. The problems offer multiple choice answers with visual aids, reinforcing spatial reasoning and accurate measurement. This foundational skill is crucial for further studies in geometry and other mathematical fields involving spatial properties and measurements.