ok so my question is calculate the perimeter of the inscribed square, given that the radius of the circle is 3 ft. I dont really understand how you would know the sides of the inscribed square.

Since the square is inscribed, it's diagonals are diameters of the circle and we can say 
 

For a square the relationship between a side and the hypotenuse is 
 
so that 
 
And the perimeter of a square is 

 




:)

What is the area of a circle that is inscribed in a square with an area of 4?

 
so  
for the circle... 
 
so