The Unit Circle?

I need help finding $P(x, y)$ from this information: the point $P$ is on the unit circle, obviously. The $y-coordinate$ of $P$ is $\frac{-1}{9}$ and the $x-coordinate$ is positive. I need help finding $P(x, y)$

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Well, the formula for a unit circle is $x^2+y^2=1$, so just plug in $y$ and solve for $x$. –  Joel Cornett Oct 21 '12 at 4:33
Any point on the unit circle is $x^2 + y^2 = 1$. You are given $y = - \dfrac19$ and $x>0$. Can you find $x$?