The Square has equall sides thus if we suppose that square has a side which is x inches then the Perimeter is :
[tex]perimeter = 4 \times x[/tex]
Thus
[tex]80 = 4 \times x[/tex]
Divide both sides by 4
[tex] \frac{80}{4} = \frac{4x}{4} \\ [/tex]
[tex]20 = x[/tex]
[tex]x = 20[/tex]
Thus each side has a value of 20 inches .