[tex]\bf x^2=0.0025\qquad \textit{let's convert the decimal to a fraction} \\\\[-0.35em] ~\dotfill\\\\ 0.\underline{0025}\implies \cfrac{00025}{1\underline{0000}}\implies \cfrac{25}{10000} \\\\[-0.35em] ~\dotfill\\\\ x^2=0.0025\implies x^2=\cfrac{25}{10000}\implies x=\sqrt{\cfrac{25}{10000}}\implies x=\cfrac{\sqrt{25}}{\sqrt{10000}} \\\\\\ x=\cfrac{5}{100}\implies x=\cfrac{1}{20}[/tex]