The document provides definitions and formulas related to mensuration, including metrics for length, area, volume, perimeter, total surface area, and lateral surface area. It discusses various geometric shapes such as squares, rectangles, triangles, parallelograms, trapeziums, rhombuses, cubes, cuboids, and cylinders along with their respective area and volume calculations. Each shape's properties and measurement formulas are clearly laid out to assist in understanding basic geometric concepts.