Consider a target board that is a square of side 14 cm. If you have a uniform chance of hitting any part of it, what is the probability that your arrow will miss the bull's eye which is a circle of radius 7cm centered at the center of the square?
Probability that you will MISS the circle:
(Area of square - Area of circle) / (Area of square)
find the area of the circle over the entire target board
then find the reciprocal of that