Rolling for Pi

Bring to class one or more large circular items such as a bicycle wheel, hula hoop or plywood disc (available a many home improvement centers). Physically measure the circumference of your circular object by marking the round item along the outside edge, and rolling it on the floor one full revolution to convert the circumference into a straight line. Next measure the diameter by finding the absolute widest measurement across the circle. Lay the diameter measurement onto the circumference line and it should go slightly more than three times. (Your results may vary slightly due to measurement inaccuracies.)