### Instruction: Points $A$, $B$, and $C$ are on a circle such that $AB = 8$, $BC = 15$, and $AC = 17$.  Find the radius of the circle.### Response: I need to find the radius of the circle, which is the distance from the center to any point on the circle.
I notice that the triangle $ABC$ is a right triangle, because $8^2 + 15^2 = 17^2$.
That means that the hypotenuse $AC$ is a diameter of the circle, so the radius is half of that.