RS Aggarwal Solutions for Class 8 Chapter 20 Volume and Surface Area of Solids, Surface area and volume are calculated for any three-dimensional geometrical shape. The surface area of any given object is the area or region occupied by the surface of the object. At the same time, the volume is the amount of space available in an object. In geometry, there are different shapes and sizes, such as a sphere, cube, cuboid, cone, cylinder, etc. Each shape has its surface area as well as volume. But in the case of two-dimensional figures like square, circle, rectangle, triangle, etc., we can measure only the area covered by these figures, and there is no volume available. The space occupied by a two-dimensional flat surface is called the area. It is measured in square units. The area occupied by a three-dimensional object by its outer surface is called a surface area.