Hi: My name is Fumiko Muhammad (mother), and I have a question in regards to my son's homework (middle school - grade 7). The following is the brief statement and the questions, The wheels on Kai's bike are 27 inches in diameter. His little sister, Masako, has a bike with wheels that are 20 inches in diameter. a. How far will Kai go in one complete turn of his wheels? b. How far will Masacko go in one complete turn of her wheels? c. How far will Kai go in 500 turns of his wheels? d. How far will Masako go in 500 turns of her wheels? The formula is : circumference = pi x diameter Please help if you can thanks Hi Fumiko, In the diagram below of Kai's bicycle wheel I have put a mark on the wheel where it touches the ground. In the second diagram the wheel has rolled one complete turn so the mark on the wheel is at the ground again. Every point on the circumference has touched the ground once so the distence the wheel has rolled is the circumference of the wheel which is 27 x pi inches. Thus in one complete turn of his wheels Kai has gone 27 x pi inches. I hope this helps, Penny Go to Math Central