A solid is a three-dimensional figure. For
example, a house brick is a solid, as it is a three-dimensional
figure. Many of the solids we come across in our world are
combinations of special types of three-dimensional figures such as
prisms, cylinders, pyramids, cones and spheres. Measurement of
surface area is very important to us if we are concerned with the
quantities of materials to be used to cover the surface area.

The sum of the areas of all external surfaces of a three-dimensional
object is called its total surface area (TSA).

Total Surface Area of a Cube

The total surface area (TSA) of a cube is the sum of the areas of its six faces.

Consider the cube shown. Each of its six faces is a square with side
length l.

Example 21

Find the total surface area of a box whose edges are all 4.5 cm long.