This unit deals with some formulae connected to proportionality between segments and Thales' theorem. Rather than giving rigorous, step-by-step demonstrations, this unit offers the advantage of verifying conclusions and properties in a straightforward manner. 

To conclude, different examples of similarity in triangles and polygons in general is also focused on, using an interactive approach.

• To introduce the concept of proportionality between segments.

• To work out the terms in a proportion.

• To introduce Thales' theorem and similar polygons.

• To construct similar polygons and understand how different measurements relate to each other.