



 
Erika, How about the wheels on a bicycle or the wheels on a car? How does the odometer in a car know how far the car has travelled? Does it use the circumference of the circular tire? The information on the hard drive on your computer or on a DC or DVD is stored in concentric circles. Why do above ground pools have a circular shape? All of trigonometry is based on the circle. In fact many books call the section on trigonometry Circular Functions. These are a few ideas. Penny  


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