



 
I have drawn the rings for the game of curling. I am going to calculate the stone ends up un the blue ring. First of all you need to assume that the curling stone is a point at a random position in the rings. The probability that it is in the blue ring is the fraction of the area of the rings that is blue. The region painted blue is the region inside a circle of radius 6 feet and outside the circle with the same center but with radius 4 feet. The area inside a circle or radius r feet is $\pi r^2$ and hence the area inside a circle of radius 6 feet is $\pi 6^2$ square feet. The area inside a circle of radius 4 feet is $\pi 4^2$ square feet. Thus the area of the region painted blue is \[ 6^2 \pi 4^2 \pi = (36  16) \pi = 20 \pi \mbox{ square feet.}\] Thus the probability that the rock is in the blue ring is \[\frac{20 \pi}{36 \pi} = \frac59\] Now you try the other colours. Penny  


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