The new length side of the perimeter, we'll call p. The original length, we'll call o. P's equation looks like this:
[tex]p = 20 \times \frac{1}{4} [/tex]
Since 5 is the length of one side, subtract 2 from 5 to get 3. The equation looks like this:
[tex]o = \frac{20}{4} - 2 [/tex]
or simply
[tex]o = 5 - 2[/tex]
