# The point P(x, y) is on the unit circle in quad IV, if x= sqrt(11)/6, how do you find y?

Oct 1, 2015

#### Answer:

$y = - \frac{5}{6}$

#### Explanation:

Since $\left(x , y\right)$ is on the unit circle
$\textcolor{w h i t e}{\text{XXX}}$x^2+y^2=1#

Substituting $\frac{\sqrt{11}}{6}$ for $x$
$\textcolor{w h i t e}{\text{XXX}} \frac{11}{36} + {y}^{2} = 1$

$\textcolor{w h i t e}{\text{XXX}} \rightarrow {y}^{2} = \frac{25}{26}$

$\textcolor{w h i t e}{\text{XXX}} \rightarrow y = \pm \frac{5}{6}$

but we are told $\left(x , y\right)$ is in Quadrant IV
therefore
$\textcolor{w h i t e}{\text{XXX}} y = - \frac{5}{6}$