Asquare is inscribed in the circle. a point in the figure is selected at random. find the probability that the point will be in the part that is not shaded.

Ok 
Probability (the point will be on unshaded part)  = area of unshaded part / area of the circle.

=   pi r^2 - s^2
                 where r = radius of circle and s = length of the side of the square.
        pi r^2