Question 743081
As if {{{y/x=1/3}}} and {{{x^2+y^2=1}}}.  Imagine the triangle, hypotenuse of 1.  {{{y=x/3}}}, so 
{{{x^2+x^2/9=1}}}
{{{x^2(1+1/9)=1}}}
{{{x^2=9/10}}}
x=
{{{x=(3/10)sqrt(10)}}} from which you can find y.