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Formula for circumference of a circle
The distance around a rectangle or a square is as you might remember called the perimeter. the distance around a circle on the other hand is called the circumference. Half of the diameter, or the distance from the midpoint to the circle border, is called the radius of the circle. |
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finding circumferenceThe circumference is the distance around the circle as shown in the picture
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finding the radiusThe same formula in terms of r is r = D/2. divide the diameter by 2 to find the radius. if you are given the diameter of the circle, simply divide it by 2 to find the radius. for example, if the diameter of a circle is 4, the radius is equal to 4/2, or 2.
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finding the DiameterThe radius is the distance from the center of the circle to its edge. for example, if the radius of the circle is 4 cm, then the diameter of the circle is 4 cm x 2, or 8 cm. if you know the circumference of the circle, divides it by pi to get the diameter
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