So the probability that a point that we select from this larger circle is also in the smaller circle is really just a percentage of the larger circle that is the smaller circle. So our probability, I'll just write it like this, the probability that the point also lies in the smaller circle, so all of that stuff I'll put in, the probability of that is going to be equal to the percentage of this larger circle that is the smaller one. So that's going to be, or we could say the fraction of the larger circle's area that is the smaller circle's area. So it's going to be 16 pi over 324 pi. And the pi's cancel out. And let's see, it looks like both of them are divisible by 4. If we divide the numerator by 4, we get 4.