If a car goes around a turn too quickly, it can leave tracks that form an arc of a circle. By finding the
radius of the circle, accident investigators can estimate the speed of the car.
Find the radius of the tire tracks. Points A and B connect to make a chord and C is the midpoint of the
chord. Notice CB is 320 ft. The distance from D to C is 80 ft. Therefore, the distance from C to the
center of the circle is (r - 80). Solve for the radius.
