Are you sure you haven't posted your formula wrong ?

Because the real formula is :

$\displaystyle T = 2 \pi \sqrt{\frac{L}{g}}$ where $\displaystyle L$ is the length of the pendulum and $\displaystyle g \approx 9.807$.

Anyway, you are given the length of the pendulum, and you know the constant $\displaystyle g$. Just plug the values into your equation to find $\displaystyle T$ for this pendulum.

So, you find $\displaystyle T = 2 \pi \sqrt{\frac{94}{9.807}} \approx 60,224270304362305376871311925823$ seconds

Yes I have a lot of figures because I use a high-precision calculator

on your calculator you should have the answer rounded around 10 decimal digits. Thus, you find $\displaystyle T \approx 60,22427030$ seconds.

I do not get the last question. $\displaystyle \pi$ is irrationnal, so you cannot express $\displaystyle T$ as a fractional number. Do they just mean round it off sensibly ?