Question 48252
1) If the circle fits exactly inside the square then the diameter of the circle is exactly equal the length of the side of the square (i.e. 8 cm)
Without a diagram, I'm assuming that the "shaded area" is the area outside the circle but inside the square.
This area is the difference in the area of the square and the area of the circle, or A(s) - A(c).

The area of the square is {{{A(s) = 8^2}}} = 64 sq.cm.
The area of the circle is {{{(pi)r^2}}} = {{{(pi)4^2 = 16(pi)}}}sq.cm.

{{{A(s) - A(c) = 64 - 16(pi)}}} = {{{16(4-pi)}}}sq.cm. This is the area of the shaded part.

2) Find the area of a circle whose diameter is 2 ft.

The area of a circle is: {{{(pi)r^2}}} where r is the radius. The radius is half the diameter, so: {{{r = 2/2}}} = 1 ft.

Using 3.14 as an approximation for {{{pi}}}, the area of this circle is:
{{{A = (3.14)(1^2)}}} = 3.14 sq.ft. Rounded to the nearest square foot, A = 3 sq.ft.