Solid geometry is a branch of geometry that deals with three dimensional space. The objects around us have different dimensions.

In this unit we will define geometric figures and then calculate the surface areas and volume of some solid figures such as prism, cylinder, cone and pyramid.

Let us consider the following figures and identify their dimensions in order to learn about geometric solid figures.

In the above mentioned figures:

1. A point has no size, hence it has no dimension.
2. A line segment and a line have no width but have length, hence they are one dimensional.
3. A circle and rectangle, have width and length but have no thickness, hence they are two dimensional.
4. A box, a cone and basketball have length, width and height and hence they are three-dimensional.

In one-dimensional figures we had been calculating length, in two-dimensional figures we had been calculating lengths of sides perimeters, and areas. In threedimensional figures we are calculating lengths, areas and volumes.