A triangle with sides measuring 8, 15 and 17 units is inscribed in a circle. What is the radius of the circle, in units? Express your answer as a decimal to the nearest tenth.
I know that the triangle is right, because 8^2 + 15^2 = 17^2 by the Pythagorean theorem. I also know that the hypotenuse of a right triangle is a diameter of the circle that circumscribes it. So, the diameter of the circle is 17 units, and the radius is half of that, or 8.5 units. 