[math] \newcommand{\mathds}{\mathbb}[/math]

Show that the probability for a length [math]1[/math] needle to intersect, when thrown, a [math]1[/math]-spaced grid is [math]2/\pi[/math], and then comment on the estimate on

[[math]] \pi=3.1415\ldots [[/math]]

that you obtain in this way.