Simple algebra.
When we convert this to an equation we get: 0.2% of something is equal to 1 unit.
So here's the equation: [tex]0.02x = 1[/tex]
After we transpose [tex]0.02[/tex], the equation become: [tex]x = \frac{1}{0.02}[/tex].
Divide [tex]1[/tex] with [tex]0.02[/tex] and you get [tex]50[/tex].
So the length of the original bar is [tex]50[/tex] cm. :D
