A square sheet of side 14 cm has a circle of diameter 14 cm drawn inside it, touching all four sides. A pin dropped on the sheet is equally likely to land at any point. Taking π = 22/7, what is the probability that it lands inside the circle?

The circle has radius 7 cm, so its area is $(22/7)\times 7\times 7=154{\text{cm}}^2$, while the square has area $14\times 14=196{\text{cm}}^2$. The probability is 154/196 = 11/14. The value 3/14 is the probability of landing in the four corner pieces outside the circle, and 11/28 comes from using a semicircle instead of the whole circle. The answer π/4 is the same for a square of any size.