# How do you change rectangular coordinates to polar coordinates?

Sep 10, 2014

You can use:

$r = \sqrt{{x}^{2} + {y}^{2}}$

If $\left(x , y\right)$ is in the first and fourth quadrant,

$\theta = {\tan}^{- 1} \left(\frac{y}{x}\right)$.

If $\left(x , y\right)$ is in the second or third quadrant,

$\theta = {\tan}^{- 1} \left(\frac{y}{x}\right) + \pi$.