The circumference of a circle with radius 6 inches is 12π inches. 15 minutes is 1/4 of the circle which is 60 minutes Therefore the tip moves 1/4 of 12π = 3π inches In 25 minutes the tip moves (25/60)12π = 5π inches Yes, you can also use the formula s = rθ θ is the angle of rotation. 15 minutes is equivalent to 90 degrees or π/2 radians Therefore s = 6 inches(π/2) = 3π inches 25 minutes is equivalent to 25/60 x 360 degrees = 150 degrees = 5π/6 radians