Problem of the Fortnight #2

 

Fodder for Thought

 

                Farmer Brown owns a goat named Calamity.  Farmer Brown is also the proud owner of a circular silo whose diameter measures 40 feet.  By some odd happenstance, Farmer Brown has tied Calamity to the silo using a length of rope that, after being knotted to the goat and the silo, measures 20*pi feet in length.  How much area does Calamity have to roam and feed if we assume that the area is determined by the land that the rope can reach?

 

Please be sure to include detailed explanations and justifications.

 

Solutions are due by 4pm on Friday, September 24th in Goodrich 108