Euler Piruleta Vs. The Braindead-Zombies

A virus from Sumatra has been introduced in a small village by an infected rat. This despicable virus turns people and animals into evil-hilarious zombies.

Fortunately, the militaries have managed to confine the civilian zombie population into a piece of land delimited by an iron fence.

However, these monstrous creatures ought to be exterminated to prevent the infection being spread all over the Earth!!

The clock is ticking!

a)  Can you calculate how many meters of titanium fence do they need to use to surround the land (to reinforce the iron fence)?

b)  Once the land is secured, it is vital to calculate its surface to produce the poisonous gas that will eradicate these evil creatures once and for all.

TIPS:  Circumference’s surface:

         Circumference’s length:

        Notice that the curved lines which join opposite vertices of a square have the 

       shape of a circumference:

Deadline: November the 28th.

Printable version available.

The idea of this challenge comes from the great Peter Jackson's 1992 film "Braindead", starring the aunt of my beloved friend and amazing Maths teacher Maria whom I would like to dedicate this crazy challenge :P Even the trailer is hilarious!

Nevertheless, if you would like to try something that is not so related to human organs, "Full Metal Alchemist Brotherhood" is probably one of the best anime series of the last few decades:

PS: Jorge, Alberto, Juan and Iñaki G handed the right solution to the last challenge!