I am a little confused by the wording on the question. It says "within the circle" but the image is of 2 squares.
I am just going to answer it as if the question said "probability that a randomly selected point within the square falls in the red shaded square."
So red square area = 3 x 3 = 9.
The area of the bigger square = 4x4 = 16.
The prob of landing in that red square = 9/16 = 0.5625 or approx 56%.