Probability =
(number or amount of possible successes)(total number or amount of possible outcomes)
Area of any circle is (pi) x (radius squared)
Area of the whole board = (pi) x (13 squared) = 169 pi square inches
Area of the shaded region = (pi) x (5 squared) = 25 pi square inches
Probability = (success area) / (total possible area) = 25pi/169pi = 0.15 (rounded)
Notice that if you do it my way ... keep 'pi' in the fraction ... you don't even
need to know what the value of 'pi' is, because there's one in the top and
bottom of the fraction, and they cancel.
