Independent, Normally Distributed R.V. Working on this:

A shot is fired at a circular target. The vertical and the horizontal
  coordinates of the point of impact (with the origin sitting at the
  target’s center) are independent and normally distributed with $\nu(0, 1)$. Show that the distance of the point of impact from the center is
  distributed with PDF $$p(r) = re^{-r^2/2}, r \geq 0.$$ Find the median of this
  distribution.

So I'm guessing this would be graphed on an X and Y axis. I can intuit that I need to take the integral of the PDF from the lower bound to $m$ (or from $m$ to the upper bound), but I don't know what the normal distribution with $\nu$(0, 1) mean.
Also, how would I show that the point of impact has the desired PDF?
Thank you.

Here's an intuitive approach: On the circle of radius $r$, the value of the joint density is $ce^{-(x^2+y^2} = ce^{-r^2}$.  The size of that region where the density has that value is the circumference of the circle, which is $(\text{constant}\cdot r)$ (not the $2$-dimensional size, of course; that is $0$).  So the probability in that region is $\text{constant}\cdot re^{-r^2}$.
