Question

Golf balls are packaged by stacking three balls vertically in a box. Given that the height of the box is 13.5 cm, and that the golf balls are touching each other and the ends of the box, what is the number of centimeters in the circumference of each golf ball? Express your answer as a common fraction in terms of pi.

Answer 1

If all 3 balls are touching each other and the top and bottom of the box, then thee diameters of the balls together is 13.5 and each ball has a diameter of 13.5/3 which is 4.5.  The circumference formula is $C= \pi d$ so $C= \pi 4.5= \pi \frac{9}{2}$ which can be expressed as $C= \frac{9 \pi }{2}$

Answer 2

13.5 / 6 = radius of 1 ball = 2.25 cm
circumference = 2pir = 2*2.25pi = 4.5pi
or
13.5/3 = diameter of 1 ball = 4.5
cicumference = dpi = 4.5pi 

4.5pi = (9/2)pi