- 1). Understand the ratio of circle dimensions. The value "pi" (3.14) is the ratio of the circumference and the diameter.
- 2). Write the equation you will perform. Since pi is equal to the circumference divided by the diameter, the equation is 3.14 (pi) = circumference/diameter.
- 3). Perform the function to solve the equation and find the diameter. For example, if the perimeter (circumference) is 8.5 inches, divide 8.5 by 3.14 to get 2.7 inches. This means that the circle has a diameter of 2.7 inches.
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