We will draw the figure
In a new scale, the new scale is
[tex]1\text{ unit= 3 cm}[/tex]
Note that the draw above is a square of side 18cm, therefore in the new scale the side of the square have to be drawn using
[tex]\frac{18cm}{3cm}=6\text{ }units[/tex]
That is, if we change the units our new square have a side of 6 units as follows
