Answered by the following sums -
Outer square area = 4x^2
side of the square = 2x which is equal to diameter of circle == diameter of inner square.
radius of circle = x
diameter of outer square = 2*sqrt(2)*x
consider side of inner square = a
so a^2 + a^2 = (2x)^2
2a^2 = 4x^2
a = x*sqrt(2)
So area of inner square will be = 2x^2
