ANSWER
[tex]Preposition:\text{ if }\frac{1}{r}\text{ is irrational, then }r\text{ is irrational}[/tex][tex]proof:\text{ suppose }\frac{1}{r}=\frac{1}{\sqrt{p}}[/tex]
where square root of 'p' is not a perfect square
[tex]Thus:\text{ }r=\sqrt{p}[/tex][tex]\text{ Therefore}:r\text{ is irrational}[/tex]
