We know that the diameter of a circle is a line that begins on one point of a circle and ends on the opposite side. We also know that the radius is a point on the circle that starts from that point and ends at the center. Therefore, the radius would be half the diameter.
i think you would add 5+4+3 and 2+3+4 and divide them so 9/12 and that makes your probability which leaves a 3/12 chance non of them are in favour of the book